The same goes for ATV parts and bike parts. As performance is what really ends up saving you money, you need to be sure to purchase these first hands. Mostly performance parts wear out after some time. For this reason you need to replace them. This needs to go on and on until the life of the vehicle. For that purpose it would be best to purchase these parts on a wholesale shop. This would allow you to pay less for per part. If you are willing to go for a second hand part then make sure that it is not repaired. Mostly crashed cars have some of these parts which are in good working condition. Purchase those off a dealer. For better rates on ATV parts or any other vehicle part it would be best that you go online.
You need not to purchase new parts which do not help the performance of the vehicle. You must have seen cars with having different colors of bumpers or doors attached to them. The reason is that these people purchase such parts second hand and them spend a little more to make them new. As such car or ATV parts do not ruin the performance; these can be afforded to be second hand or repaired.