They can think of anything to deny your claim (they can't legally void it)
Rims will make your CD player f*ck up "ride's too bumpy"
Lowering the car will put added stress in various bits of your steering
Short shifter - obvious nono
Body kits shuoldn't screw warranty
Any I/H/E will screw warranty for sure. "engine's not designed to be less restricted"
Anything electrical will kill warranty, unless it goes through the ciggy lighter, or you install a fuse tap.
Installing audio (amps, subs, changing the HU) will cause more current draw which could flatten the battery or making ur alternator work overtime -
Don't change bulbs - could draw too much or too little current.
so basically, they can find a reason for anything.
-However!-
If your engine block cracks, and you have instane ICE installed, that has nothing to do with your engine - it's impossible to prove that the ICE did sometihng to your engine block.
If your rear shock absobers make a clicking and popping sound when you turn, and you have a fart can installed - it's impossible to prove that the exhaust system did sometihng to your rear shocks.
If your steering rack fails and you have a CAI. - that can't be proven either.
Just stay logical and be prepared for consequences should things go wrong, and keep all your stock parts just in case you need to put things back for warranty claims :)
oh, and be careful too - most dealers are not stupid, and it's very offensive to them if you try to hide things like that.
edit: wtf is a gear shift knob going to do to your car? make you mis-shift? and blow your engine? lololol
rep plx? :D