Aftermarket parts can be a double-edged sword; they can make or break your car. They are affordable, and you can find many of them even down the street, but that’s the thing, since there are many aftermarket parts out there, you can also get fooled by them. Worst-case scenario, you might have bought one and you haven’t noticed yet that your car could break down any moment. 

At Mars Performance, we understand how every car owner feels when upgrading their vehicle with aftermarket accessories like it can feel like unlocking a new level of performance, comfort, or style. But here’s the truth: not all aftermarket parts are created equal.

While some upgrades deliver real value, others underperform or worse, it can cause damage and costly expenses. In this guide, we’ll unpack why some aftermarket parts fail, and how you can avoid costly mistakes with smart choices.

Common Reasons Aftermarket Parts Fail

1. Poor Quality Materials & Manufacturing Deficits

Cheap aftermarket parts or low-cost options often cut corners since manufacturers make them using substandard materials like thin plastics, low-grade metals, and unreliable electronics, meaning they wear out faster. As they use low-quality parts it can compromise the safety or your vehicle since sometimes they skip safety testing and do not undergo the same rigorous evaluation as OEM or premium aftermarket brands

There is also the issue of poor casting or machining. Casting and machining are critical processes in manufacturing metal components like engine parts, suspension arms, brackets, and housings. When done improperly, these flaws often lead to structural weakness, poor fitment, and premature failure.

2. Compatibility Issues

This is one of the common mistakes when you’re buying auto parts and that is failing to know your vehicle’s fit and specifications. Which is wrong practice because every vehicle has unique requirements, from its engine type, year, model. Even if a part seems like it will fit, slight differences in specifications like wiring connectors, mounting points, or part dimensions, can create problems.

3. Buying Parts Without Research

Buying without proper research is one way to ensure you’re breaking your wallet while not thinking about your car. Many buyers often jump into purchasing parts without conducting proper research, which leads to poor-quality materials, incorrect parts, and components that don’t meet the vehicle’s needs. 

4. No Safety or Compliance Certification

Not all parts on the market meet ADR (Australian Design Rules) or international safety standards. Using uncertified parts can lead to legal issues or failed inspections. If they do not comply with the relevant ADRs prescribed to their respective state, authorities may deem the vehicle unroadworthy and liable to be de-registered. Meeting ADR-compliant gear guarantees safety and quality, and it won’t compromise your safety and your car’s.

5. Bad Installation Practices

Some aftermarket parts are marketed as "universal," which is why they often lead to poor fitment and installation difficulties. Attempting DIY repairs without proper knowledge can worsen the problem and create safety hazards. It can lead to part failure even if the product itself is fine. Common issues include incorrect torque settings, skipping calibration steps, or faulty wiring.

6. Overmodding Without Supporting Upgrades

Adding one high-performance upgrade without balancing the rest of your system can overwhelm your vehicle. For example, installing a performance chip without upgrading fuel or cooling systems can do more harm than good.

7. Not Verifying the Return Policy

Not all parts have a return policy, especially if you’re buying online. Some sellers vanish after the sale, offering no way to return a faulty part or get technical assistance. Without warranty coverage, you’re on your own if something goes wrong. 

How to Avoid These Costly Mistakes

Now that we’ve identified the common mistakes with aftermarket parts, it’s important to address them and ensure you’re investing in quality components for your vehicle. Here are a few tips to help you make the right choice:

1. Identify correctly if it’s a OEM or Aftermarket

It’s essential to know whether the parts are made by the original manufacturer of your vehicle, the same parts that came with your car when it was built, or if they are produced by third-party manufacturers, as quality can vary depending on what you need. If you're identifying parts based on your specific needs, you can check out this helpful OEM vs. Aftermarket Car Parts Guide by Mars Performance for a deeper comparison.

2. Research & Reviews First

After reviewing what you want to get, whether the OEM or an aftermarket, it’s important to look up brand reputation because it impacts customer trust, and with a good rating and services, that means it can affect buying decisions. If you’re looking for reputable brands, it’s a must to use forums, video reviews, comparison blogs, and also because with reputable brands, that means they have undergone testing and passed the ADR guidelines too.

3. Ensure Proper Fitment

Make sure you research what you need for your car, and ensure that it’s the right model, with the correct specifications and fit for your vehicle. Researching is important, and you can do that by having your vehicle’s information on hand, including the VIN (Vehicle Identification Number), which helps pinpoint the exact parts you need. Additionally, you can also refer to your owner’s manual for specific details or use fitment checkers to match parts to your car.

4. Choose Quality Over Pricing

It may hurt your budget in the short term, but it’s important to focus on the quality of the parts over their price. By doing so, you’re ensuring better performance and durability, which ultimately saves you money and time in the long run.

5. Get Professional Installation (When Needed)

Know when to ask for help, especially when installing car parts—if you’re not a professional. Recognising when DIY isn’t worth the risk helps ensure the car parts you purchased are used wisely and installed properly. It’s better to consult a professional mechanic than try to do it all yourself. Mechanics can provide expert advice and make sure the parts are fitted correctly and safely.

6. Think in Systems Not Parts

Upgrading one part without considering how it affects the rest of the car can lead to imbalance, inefficiency, or even failure. Instead of making all your changes at once, approach your upgrades in logical, planned stages. Start with a clear goal, like better off-road handling, increased horsepower, or more towing capacity, and build your upgrade around that.

Furthermore, one of the most common mistakes is focusing on power upgrades while ignoring safety and handling. So, with every upgrade, you must ask yourself: “Can my current setup support this?” If not, consider pairing performance enhancements with supporting modifications to maintain a safe and efficient system.

7. Verify the Return Policy

As we said, not all auto parts come with hassle-free return policies. That’s why before purchasing, always check the retailer’s return and exchange policies. It’s better to go for retailers that offer flexible return options, especially if you’re not sure about the compatibility of the car part that you will buy. 

Red Flags to Watch Out For

When shopping for aftermarket parts, it’s easy to get drawn in by flashy listings or those unbeatable prices, but these are often signs of a bad deal and it’s a no no. Here are the red flags to look out for before making a purchase:

🚩 Too-Cheap Prices

If a price seems too good to be true, it probably is. Extremely cheap aftermarket parts are often made from inferior materials or could even be counterfeit. While it may save money up front, these parts can cost more in the long run due to premature failure or damage to your vehicle.

➡ Smart tip: Always compare prices across trusted sources like Mars Performance, which offers performance-tested, ADR-compliant accessories with quality assurance.

🚩 Vague or Missing Product Information

If a product listing doesn’t provide details such as material type, compatibility (make/model/year), or performance specs, it’s a major red flag. When there’s a lack of transparency that usually indicates poor quality or an attempt to hide limitations.

➡ What to look for: Descriptions that clearly state whether a part is OEM-compatible, what it's made from, and what performance benefits it offers.

🚩 No Contact Info or Warranty Policy

Reliable suppliers stand by their products. If there’s no return policy, no warranty, or no visible customer service contact, you’re likely dealing with a vendor who won’t support you if something goes wrong.

➡ With Mars Performance, all products are backed by clear warranty policies and an experienced support team, so you can buy with confidence.

Conclusion: Shop Smart, Drive Smarter

When you’re buying car auto parts, it doesn’t have to be stressful. You just have to avoid the common mistakes every other car owner (who won’t listen) makes and make rightful decisions. There are many benefits to upgrading your car, but knowing the right upgrades can transform your driving experience—but only if you shop wisely.

From avoiding fake parts to understanding how one upgrade affects your whole system, smart choices lead to better performance, a longer lifespan, and safer driving. By following the guide, reading thoroughly, and understanding it, you can ensure that you’re getting the right parts to keep your vehicle running smoothly, and your car will love and thank you for it.

For a hassle-free experience and high-quality parts, we recommend shopping at Mars Performance. They offer a wide range of reliable products tailored to meet your vehicle’s specific needs. With Mars Performance, you can trust that you’re making the right choice, ensuring your car stays in peak performance.

Explore Mars Performance’s wide range of ADR-compliant, high-quality aftermarket parts designed for both performance and style. You can have peace of mind knowing you’ve avoided the common pitfalls of buying auto parts. Keep your vehicle in top shape with the right parts and expert advice from Mars Performance.