Aftermarket parts are both convenient and affordable -- you just need a little guidance to make sure that you get the right part for your vehicle. Aftermarket parts are designed to be identical in most respects to your original manufacturer's parts; they've just been produced by a third party at a lower cost.
1. Getting the Wrong Make or Model
Aftermarket parts are highly specific. There are special parts for each make or model -- you need to know exactly what type of car and what type of trim package you have if you're going to get the right part. Ideally, you should look at the manufacturer's number on the part itself and find a replacement that correlates.
2. Assuming All Aftermarket Parts Are Identical
Just with any other product, there are different companies that manufacture aftermarket parts. Some manufacture very cheap replacement parts that are designed to get your vehicle up to standard, while others manufacture parts that are better than the parts that traditionally come with the vehicle. If you see large gaps in pricing, you can assume that the parts have a difference in quality. This is especially true with high performance auto parts.
3. Purchasing From a Middleman
When purchasing aftermarket parts, it's usually best to go through a licensed distributor of these parts. Aftermarket parts can be sold by consumers, especially hobbyists who may not have need of them -- but these parts won't usually still be in warranty and may be used. Purchasing parts through a licensed distributor will give you the assurance that the part is of high quality and that you can get it replaced if it doesn't work properly with your vehicle. Contact a business, such as Yearwood Performance Center, for more information.
4. Not Taking Into Consideration Appearance
Aftermarket parts are designed to be functionally identical to the manufacturer's parts, but that doesn't mean that there may not be minor cosmetic differences. If you're purchasing a part that requires some symmetry (such as a single headlight cover), you may want to check to make sure that the part looks the same as well as functioning the same. Some aftermarket parts may be intentionally designed to appear differently.
As noted, not all aftermarket parts are made equal. It's usually ideal to consult with your mechanic regarding the parts that you actually need. Mechanics are usually more than willing to order in and work with aftermarket parts upon request -- and they will know the cheapest and most trustworthy places to purchase them from.