Also depends on what dealer you go to, some are very picky.Modding is the VERY reason I did not get an extended warrenty, and I am very glad I didnt.As for first mod, spend $50 and get a K&N, it will give you a HP or so, change the exhaust and engine sound slighly at WOT and will keep you happy for a little while, next focus on exhaust, its your best bet for quick fairly cheap HP on these cars.Mods on the engine side dont seem to do much according to the dyno. CAI isnt worth the 1-5 HP gain over just a K&N IMO, too much $$$. Steeda UD pullies will give 6-8RWHP (dyno proven 6RWHP on 01 bullitt), upper plenium and TB= 6-10RWHP (also been dyno proven), hypertechs power programmer gave an 01 bullit 3peak RWHP and those gains were typical thoughout the rest of the curve(not worth 300 big ones IMO), not sure on the other brands though, should be simular gains with steeda T/A.Hope that helps.