guide
Genuine or aftermarket parts? Which to pick, part by part
What is the difference between genuine (dealer) and aftermarket?
Genuine (dealer) comes to the manufacturer's own specification with its original (OEM) part number, and it is what the dealer fits. Aftermarket is made by an independent company to fit in place of the genuine part. Its quality ranges from suppliers who also make parts for the factories, down to cheap products that ignore the specification. The price difference is real. The quality difference depends on the part and the manufacturer.
When is genuine required?
For parts that talk to the car's computer, or work under high heat and pressure:
- Engine & transmission: hydraulic engine mounts, internal gearbox parts, gaskets.
- Electrical & battery: sensors, electronic modules, wiring.
- Spark plugs & coils: coils especially, because a weak coil shows up as a misfire and an engine warning light.
In these categories, a small saving can cost you removing the part twice, or a bigger failure.
When is good aftermarket enough?
For wear items and simple mechanical parts, provided the manufacturer is known:
- Brakes & pads: pads and rotors; brands available on Speero include Bendex and Power Stop.
- Oils & filters: oil, air and cabin filters.
- Suspension & arms: shock absorbers from KYB or Monroe are a known choice.
- Lighting and Mirrors: DEPO and TYC are among the aftermarket brands available.
- Bumpers & grilles: aftermarket is fine if you match the trim and the sensor holes.
A/C & cooling sits in the middle: the radiator and evaporator accept a good aftermarket part, while the compressor is better genuine or from a manufacturer such as DENSO.
How do I compare one aftermarket part with another?
- 1Match the original part number: a good aftermarket part states the OEM number it replaces.
- 2The manufacturer's name is clear on the part and the box, not just 'Taiwanese' or 'Korean'.
- 3Compare the price with genuine on the same page: if the gap is small, genuine is the better buy.
- 4Read the specifications: side, trim and compatible years.
How do I tell them apart on Speero?
Every listing states the part type, and every part number has a page showing genuine and aftermarket side by side with price and sellers. Select your car once and you see only the parts that fit it. We check fitment before shipping, and returns are accepted within 14 days of delivery.
