I do not mean to say this in any insulting manner and I am not trying to be a dick, but honestly, this kind of crap annoys me.
Honestly, they can void your warranty for the mods you have like the first guy who replied said.
As someone who used to work with this kind of stuff for a living I am going to give you one peice of advice now. ALWAYS ALWAYS ALWAYS ask the dealership if the mods you want to get are okay and will not affect your warranty in any shape, way or form - with these cars i strongly urge and recommend people to KEEP their warranties. For me at least, the warranty has already saved me 3500$ in repairs - in the 7 months I own the car!
There is nothing worse than having customers come in who have beat the piss out of their car - like the first guy said - and then complain that their warranties are done...
Sometimes it is honestly like...REALLY WHAT DID YOU THINK WAS GOING TO HAPPEN....
The only thing I can advise you is to go to other dealerships and try there. Also you could do your best to dispute it, but don't forget who will most likely win if they find that your mods are the cause!