Altering your car in any way usually results in a voided warranty especially when you increase horse power. Some things will not void your warranty, its pretty much up to SOA on what they will allow. As far as the intake the SPT intake sold by Subaru is fine with me, I run it and have no problems but a lot of people on here will tell you not to put one on just b/c the stock one is already high flowing.Just bought a 2007 factory rep. WRX Wagon. I see Subaru sells an air intake system. Just curious if the K & N, for example, would void warranty. Anyone have suggestions on best H.P. mods to do that will not void warranty?