I think it really depends on the dealer. I think some guys on here said they have found "mod friendly" dealers. I asked mine just a general question about mods and warranties and he said if you add something or tune the car and then something happens, your warranty is void, with the exception of Axlebacks. I would call your dealer or other dealers in the area, tell them what your plan is and ask if it'll void your warranty should you have any problems later on.
2012 Race Red GT/CS: BBK X-Pipe, Flowmaster Outlaw mufflers, Barton Shifter