How to Choose the Right Side Skirt Car Mods: A Complete Beginner’s Guide

If you’ve been searching for ways to instantly upgrade your vehicle’s look without breaking the bank, you’ve probably come across the term side skirt car mods. And for good reason, side skirts are one of the most underrated upgrades that can completely change the way your car looks and performs. 

In a world where performance and style matter more than ever, side skirts stand out as the perfect combination of form and function. With this simple addition, it sharpens your car’s appearance while offering real aerodynamic benefits.

In this guide, we’ll break down what side skirts actually do, how they affect your vehicle, how to choose the right materials, and how to select the perfect side skirts for your build—whether you prefer universal options or model-specific kits. (Psst: Mars Performance carries both. Check out our Side Skirts Collection.) We’ll also show you the most common mistakes to avoid when shopping for quality aftermarket aero.

By the end, you’ll have the confidence to choose, install, and maintain your side skirts like a pro.

What Are Side Skirts?

Side skirts or car side skirt are long panels installed along the lower sides of your car. Their primary job is to reduce air turbulence as the vehicle moves. As air flows along the sides, side skirts help keep that air from “spilling” underneath the vehicle, reducing lift and improving stability.

Aside from function, side skirts dramatically improve styling. They make the car appear lower, sleeker, and more premium. Whether subtle or aggressive, side skirts for cars are one of the easiest ways to elevate your build.

Here’s the thing, because it’s easy to confuse side skirts with other aerodynamic parts, they differ from rockers, splitters, and diffusers:

1. Rockers (or rocker panels) sit in the same area as side skirts, but they are structural components built into the car’s body. Side skirts attach over or along these rockers; they don’t replace them.
2. Splitters are installed at the front of the vehicle which seals the airflow in front. Their job is to push air upward and create downforce on the front end. Side skirts, on the other hand, manage airflow along the sides, not the front.
3. Rear diffusers are installed under the rear bumper and help control how air exits from underneath the car. They reduce lift at the back, while side skirts control the airflow between the front and rear wheels.
4. Side skirts specifically manage side airflow, reduce turbulence, and visually lower the vehicle. Additionally, it acts as a lateral barrier to stop airflow from spilling sideways and entering the underbody. 

In performance & racing applications, side skirts help maintain a stable low-pressure zone beneath the car by preventing high-pressure side air from entering underneath. Take note, they are part of the aero package but serve a different purpose from splitters and diffusers.

What Is the Point of Side Skirts in a Car?

You might ask what side skirts do for your car and why you should add them. The primary function of side skirts is to reduce aerodynamic drag, which enhances the car’s performance. Additionally, in modern automotive design, they contribute significantly to a sleek and refined appearance.

Drag is the force that opposes the motion of an object moving through a fluid such as air. When you reduce the amount of air that flows underneath the vehicle, side skirts improve stability and allow better heat dissipation around performance components.

As a result, cars with excellent aerodynamic design can reach higher speeds and achieve better fuel economy than cars with poor aerodynamic design. With the help of side skirts, drag becomes more manageable at higher speeds, allowing the car to move more efficiently.

Black running boards and side step nerf bars for BMW X5 F15 2013–2018 an aerodynamic-style body kit upgrade for improved appearance and fitment.

Why These Side Skirt Car Mods Matter for Everyday Drivers

Side skirts aren’t just for show cars or high-performance builds, they offer practical benefits even everyday drivers can appreciate. You don’t need a race car to appreciate aero upgrades. Even if you’re not hitting high speeds or tracking your car, side skirts still improve how your vehicle looks, feels, and behaves on the road.

1. They make your car more stable at regular speeds

By preventing air from rushing underneath the vehicle, side skirts reduce turbulence and lift. Creating a smoother, more planted driving experience, especially on highways or windy roads.

2. They improve fuel efficiency (even if only slightly)

With smoother airflow around the vehicle, your engine works a little less to push through drag. It’s not a dramatic change, but over time, better aerodynamics can contribute to improved mileage.

3. They protect your lower panels

Because they extend downward, if you drive on uneven roads or gravel, they help protect your rocker panels from scratches and chips. Side skirts act as an extra barrier against rocks, road debris, and dirt.

4. They upgrade your car’s appearance

Unlike high-performing cars that focus on speed, style, and function, everyday drivers look for car parts and accessories that can enhance their vehicle’s style. Adding side skirts delivers exactly that since it gives your car a lower, sleeker, more modern look, even if you don’t upgrade anything else on your vehicle.

5. They add value to your build without costing a fortune

Compared to full body kits or performance-heavy mods, side skirts are affordable and easy to install. They’re one of the best bang-for-buck upgrades for anyone who wants a noticeable transformation.

6. They work well with future mods

If you plan to add a front lip, rear diffuser, or wheels later, side skirts help create a cohesive look. They’re a foundational mod that fits into almost any long-term upgrade plan.

To put it simply, with all these practical advantages, side skirts stand out as one of the most affordable and effective upgrades Australian drivers can add to their vehicles. Imagine being able to drive long distances without having to stop for gas or being able to accelerate and maneuver through corners with ease. With car side skirts, you can achieve these benefits and more.

Types of Side Skirts 

Side skirts come in different styles and materials, each offering a unique look, level of durability, and fitment quality. There are OEM side skirts, which manufacturers offer and are often found on sportier trims (like BMW M Sport or Honda Si), and aftermarket side skirts, which come in various styles, materials, and finishes which range from subtle lips to extreme flared designs.

When talking about the different types of side skirts, there are universal and model-specific options. Understanding these helps you choose the right side skirts for your driving style, vehicle type, and budget.

Universal Side Skirts

Universal side skirts fit a wide range of cars because they use adjustable lengths and flexible materials. They are easy to trim or adjust, which makes them a good choice for beginners. Universal skirts are ideal for simple style upgrades because they are easy to install, budget-friendly, and allow you to enhance your car’s look without worrying about exact model fitment.

Model-Specific Side Skirts

As the name suggests, model-specific side skirts are designed for your exact make, model, and year, offering the most accurate fit and cleanest installation. They provide exact fitment with no major trimming needed, and they remain more stable at higher speeds. If you want a premium upgrade with precise lines and factory-level fitment, model-specific side skirts are your way to go.

Common Side Skirt Materials

What are the best side skirts for Australian cars?

There are no right answers when it comes to the best side skirts for cars because the “best” side skirts depend on the specific car model and user preference. However, there are popular options for Australian cars, including premium aftermarket Australian brands like Mars Performance, for a simple, easy installation and high-quality construction built for Australian conditions. 

If you’re looking for the best side skirts for Australian cars, it usually starts with understanding your vehicle type, your daily driving conditions, and the overall style you want to achieve. Australia’s road conditions, climate, and vehicle preferences all play a role in what type of side skirts will work best. So here are our recommendations:

Best Side Skirts Based on Vehicle Type

Sedans

With clean, OEM-style or slightly aggressive side skirts. Sedan has these enhanced sleek side profiles while maintaining good ground clearance which are important for Australian streets, speed bumps, and sloped driveways.

Hatchbacks

Hatchbacks benefit from slightly extended or sportier designs that add more presence and balance out their compact shape. Sportier skirts help give hatchbacks a more dynamic look without overdoing it.

SUVs & 4x4s

For SUVs and 4x4s, PP (polypropylene) skirts or rugged running-board-style skirts are ideal. They’re flexible, crack-resistant, and durable that are perfect for gravel roads, rough terrain, and Australia’s unpredictable road conditions, especially when you’re on the road for that adventure. 

Performance Cars

Performance cars pair best with ABS, carbon fibre, or hybrid composite skirts. These materials offer improved aerodynamics, enhance the car’s sporty lines, and reduce weight for better handling.

Best Side Skirts Based on Your Driving Style

1. Daily Driving: ABS or PP skirts are the most practical because they handle bumps, potholes, and everyday wear without cracking. They offer a good balance of style and durability.
2. Highway / Long-Distance Driving: Choose sleeker, aerodynamic side skirts. They help smooth airflow and improve stability at higher speeds, especially useful for long open stretches of Aussie highway.
3. Track-Inspired or Spirited Driving: Carbon fibre or composite skirts offer better stiffness, lighter weight, and improved aerodynamic performance. They also match the aggressive styling of performance mods.
4. Off-Road Driving: It’s obvious that PP skirts are the best choice for off-driving since they can flex on impact and resist cracking. They are ideal for Aussie off-road conditions, beach driving, and gravel tracks.

Best Side Skirts Based on Your Budget

When we talk about budget, a budget-friendly side skirt option means going for universal ABS or PP skirts. These are affordable, easy to trim and install, and great for simple style upgrades. They offer a quick way to enhance your car’s look without overspending. 

But if you have more budget, you can go for model-specific ABS skirts as they provide excellent fitment with no trimming needed and are more stable and durable long-term, making them a reliable option for everyday driving. 

Lastly, if you want a premium look for your car, choose carbon fibre or hybrid composite skirts. These are lightweight, strong, and aerodynamic, delivering high-end styling perfect for performance builds and show cars.

Fitment & Installation Considerations

Choosing the right side skirt isn’t just about style—it’s also about fitment and installation. Poorly fitted skirts ruin the car’s aesthetics and can even affect driving performance, and you don’t want that, especially since mistakes can add more to your budget. Here are some installation tips you need to consider:

• Always test-fit before securing the side skirts.

• Use proper tools like a drill, trim removal tools, screws, or double-sided automotive tape (depending on the kit).

• Ensure both sides sit evenly to avoid misalignment.

• For carbon fibre or composite skirts, avoid overtightening to prevent cracks.

• Hire a professional installer if you want perfect alignment or if your kit requires drilling.

Final Checklist Before Buying

Before choosing the right side skirts for your vehicle, it’s worth taking a moment to understand how car modifications are treated under Australian insurance and legal standards. 

Even factory-style side skirts may fall under modification guidelines depending on your state. To help you make the right decision, Mars Performance has helpful resources that explain how to modify your car without affecting your insurance and break down the key car modification laws in Australia.

And before you hit “Add to Cart,” run through this quick checklist to guide before checking out:

✔ Confirmed the exact make, model, and year compatibility
✔ Chosen the right material for your driving style
✔ Checked ground clearance and daily road conditions
✔ Decided between universal or model-specific fitment
✔ Reviewed installation requirements (DIY or professional)
✔ Selected a reliable brand or supplier
✔ Ensure the style matches your overall build

Conclusion

Choosing the right side skirts doesn’t have to be overwhelming. It’s simple, once you understand your vehicle type, driving habits, material options, and fitment needs, you’ll know exactly what to look for. 

Side skirts offer one of the best upgrades for style and subtle aerodynamic improvements—giving your car a lower, sleeker, and more confident look on the road and yes they are more than just cosmetic upgrades.

Whether you’re aiming for a simple refresh or a full custom build, the right side skirts can transform your vehicle’s presence instantly. Just make sure you understand the installation costs and comply with your insurance requirements before upgrading.

Ready to unlock your vehicle’s full potential? Explore Mars Performance’s premium aftermarket accessories from side skirts down to wheels, and experience the styling and performance-enhancing advantages for yourself.