CAI for 535

You are better off investing in an FMIC and just getting DCIs.
Injen is a lotta dough for no gain. The long piping represents a restriction, so I doubt it is much better than your stock airbox. I know it looks cool, but it is just not proven to be more efficient.
The really serious guys who hold world records at the track just use normal open cone DCIs. That should tell you something. They are mounted snugly on the intake for a shorter distance between open air and the channel it has to pass through. BMS sell them for $95 i think.
A CP-e or Helix FMIC is $900, but that will give you some serious cooling of IATs and a noticable gain in power. About 25 hp at the crank. DCI adds 10-15 hp at higher revs. I have seen the dynos.

A dealership isn't going to void your warranty just because they see it on the car, that's illegal. That part has to cause damage to a warrantied part of the car in order for it to of course be voided out. For example if you buy lets say a short shift kit, and your transmission gears go bad, well then they could possibly void that transmission warranty, but NOT the maintenance warranty. It's been discussed quite a lot on this forum and many others... Do a search, or just read about the Magnuson and Moss warranty act.