This has been asked time and time again. So search will yeild the best results for you. Theres a lot and nobody is prob going to want to give you the full story here. But the basic jist of it is that the government set up regulations that states manufacturers cannot void or decline warranty service simply for the fact there being a visually detectable aftermarket device on the vehicle in question. The manufacturer must prove that the aftermarket part was the strict cause of whatever malfunction the vehicle experienced. And if so proven they can and will not uphold your warranty. But the have to prove it and hand it to you in writing. Now, theres a but. This is a MASSIVE hassle to go through with the dealers, regulations, gov. etc.

So unless you're either
a. prepared to do a lot of research come a time something may go wrong or
b. going to purchase parts that really cannot at all potentially damage your engine or suspension etc. which there are few.

Wait out your warranty. Most peeps choose not to, and I know it may be hard as all hell to have a nice car sitting there with tons-O-potential with no love. But hey...you're writing your own ticket at this point. The balls in your court roll it as you please.

BTW, hope that helped a little. Do a search for more info