If you bring your car to your car brand model shop like Toyota, Honda, and many more to fulfill their service, car maintenance, or for a repair, an experienced mechanic will fit your vehicle with genuine OEM parts that fits your car model.

However, if you bring your vehicle for maintenance, repair, or an upgrade to an independent shop or aftermarket shop like Mars Performance, you need to know that aftermarket parts will be used to service your vehicle. For a deeper dive into how aftermarket parts compare with OEM, check out our Aftermarket Car Parts and Accessories Guide.

Have you noticed the difference based on this lingering question alone? Well, that’s what we’re going to talk about today, the difference between OEM and aftermarket parts.

Difference Between OEM and Aftermarket Parts

What Are OEM Parts?

OEM stands for Original Equipment Manufacturer. These parts come from your car's original producer or a subcontracted supplier. When you buy an OEM part, you essentially get the same component that came with your vehicle from the factory, which ensures a perfect fit and reliable performance.

Pros of OEM Parts

• ✅ Guaranteed Fitment: Perfectly designed for your specific make and model.
• ✅ Manufacturer Warranty: They are often covered under your vehicle’s warranty.
• ✅ Consistent Quality: Meets original specs and materials.
• ✅ High-Quality Performance: OEM parts ensure your vehicle performs at its best.

Cons of OEM Parts

• ❌ Higher Cost: OEM parts often come with a premium price tag as they came from original manufacturers. 
• ❌ Limited Choices: They lack flexibility so you're stuck with factory design and options.
• ❌ Availability Delays: Sometimes OEM parts are harder to find, especially for older or discontinued models.
  

What Are Aftermarket Parts?

Aftermarket parts come from companies other than the vehicle’s original manufacturer, so they don’t qualify as OEM. Their quality can vary significantly based on the materials, manufacturing processes, and quality control standards. In many cases, they even surpass OEM quality, especially when you source them from trusted brands like Mars Performance.

They offer an expansive range of aftermarket car parts and accessories such as headlights, body kits, wheels, performance upgrades, and more, which are all designed to make your car upgrade the look and feel of your ride.

Pros of Aftermarket Parts

• ✅ Affordability: Usually more cost-effective and budget-friendly than OEM.
• ✅ Customisation Options: You can choose from a wide variety of styles, materials, and finishes.
• ✅ Enhanced Performance: Many aftermarket upgrades are designed to improve speed, handling, lighting output, and overall functionality.
• ✅ Readily Available: Easier to source, especially for popular makes like Subaru, Ford, VW, and BMW as there are many retailers out there.

Cons of Aftermarket Parts

• ❌ Quality Varies: Choosing the wrong brand can lead to inferior quality, which is why sourcing aftermarket parts from reputable suppliers matters.
• ❌ May Require Professional Installation: Especially for advanced mods like LED headlight conversions or custom aero kits.
• ❌ Vehicle Warranty: Installing aftermarket parts on your vehicle may void your warranty coverage.
• ❌ Overwhelming Availability: With so many aftermarket parts flooding the market, you may face a large and often confusing selection when shopping on your own.

When to use OEM or aftermarket parts

Choosing between OEM and aftermarket parts comes down to what matters most to you. So let’s help you decide, if one of the scenarios below ranks high on your list, you’re likely to prefer one option over the other.

Your Vehicle Is Under Warranty

If you're keeping your vehicle under warranty or it is still under manufacturer warranty, using aftermarket parts might affect coverage. It's better to stay with the manufacturer's service because, in the worst-case scenario, the warranty provider can deny coverage for a repair if they notice that an aftermarket part replaced the original and it caused the issue.

✅ Consider: OEM parts

You Want to Customise Your Car

OEM parts are built to keep your car stock. But if you're looking to upgrade your vehicle’s appearance or performance with features like headlights, body kits, grilles, taillights, bumper bars, spoilers, aero kits, or alloy wheels—aftermarket is the only way to go.

✅ Consider: Aftermarket parts

✅ You Want Guaranteed Compatibility

If you're worried about quality or whether a part will work properly, OEM parts provide peace of mind since they come from the original manufacturers, the same as your car model. They fit your exact make and model and typically include a warranty, ensuring worry-free operation.

✅ Consider: OEM parts

💸 You're On a Tight Budget

Car repairs can strain your finances, and delaying them can lead to bigger (and more expensive) problems. If OEM parts are too pricey and you're looking for affordable or high-performance alternatives like those from Mars Performance, it can deliver solid performance without the premium price tag.

✅ Consider: Aftermarket parts

You Want Long-Term Reliability

If your goal is to reduce trips to the mechanic and avoid frequent part replacements, OEM parts might be the better route. They’re designed to meet factory standards and usually come with a manufacturer-backed guarantee.

✅ Consider: OEM parts

You Need a Quick Repair

When time is critical, part availability becomes key. OEM parts may need to be ordered, causing delays, and in some cases, they’re no longer available because certain parts have been officially discontinued. In contrast, aftermarket parts are more widely available. You can find them both online and in physical stores or maybe even just down your street. The best part? If you’re buying online, especially from Australian suppliers like Mars Performance, they often ship faster and get to you when you need them most.

✅ Consider: Aftermarket parts

OEM vs Aftermarket: Which Should You Choose?

In the debate between OEM and aftermarket parts, there's no right or wrong answer, it all depends on what your car needs and what you have. Whenever you’re given the choice, ask for estimates on both options so you can weigh them wisely.

You can rely on your original manufacturer for service and genuine OEM parts during repairs. But you can also trust a specialist retailer like Mars Performance to provide high-quality aftermarket parts, expert support, and a seamless buying experience tailored to your vehicle.

With years of experience serving the Australian automotive market, Mars Performance delivers and continues to deliver with their wide range of aftermarket parts and accessories. No matter what make or model you drive, we’ve got something for you.

OEM is safe. Aftermarket is smart. Mars Performance is better.