When you need a part, you're usually offered two options with a large price gap between them: an original part from the dealer, and an aftermarket one from another manufacturer. The question isn't which is better in the abstract, but which is right for this particular part on this particular car. The difference between those answers can be double the price — or the life of the engine.
| Part type | Recommendation | Why |
|---|---|---|
| Braking and suspension components | OEM, or aftermarket from a known brand | Safety parts — a failure here can't be repaired afterwards |
| Sensors and electrical parts | OEM | A non-matching sensor confuses the car's ECU |
| Timing belts and chains | OEM | Failure can destroy the engine entirely |
| Oil and air filters | Aftermarket from a known brand | Small quality gap, large price gap |
| Cosmetic parts (mirrors, handles, covers) | Aftermarket or used | No bearing on safety or performance |
| Lamps and glass | Good aftermarket | Available at comparable quality for clearly less |
The closer a part sits to one of three things — stopping the car, steering it, or protecting the engine — the more the original is worth paying for. The further it sits from those, the more the price gap matters and the less the quality gap does.
An original used part can beat a cheap aftermarket one for fixed mechanical and structural components. But avoid them for anything that wears by design: filters, belts, and brake friction parts. Our guide to used parts covers what is worth buying second-hand and what isn't.
The most accurate way to order the right part is the part number itself, not a description. The same component can differ between two production years of the same model. Take the number from the old part if you can, or give the seller your chassis number — see our chassis number guide.
Don't buy "always original" or "always cheapest". Classify the part: if it relates to stopping, steering or protecting the engine, pay for the original. If it doesn't, a known aftermarket brand saves you money without the risk.
Browse the parts listings, and read how to spot counterfeit parts before buying.
OEM comes from the same manufacturer that supplied the part fitted at the factory. Aftermarket comes from a different manufacturer and varies enormously in quality. Counterfeit is not a third category but a forgery carrying a mark it has no right to.
The closer the part sits to stopping the car, steering it, or protecting the engine: braking and suspension components, sensors and electrical parts, timing belts and chains. A failure in any of those cannot be repaired afterwards.
Oil and air filters from a known brand, cosmetic parts such as mirrors, handles and covers, and lamps and glass. The quality gap is small, the price gap is large, and none of them bear on safety.
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