Nice rig mate! Ive got the 2nd CAI and a K&N filter, and had my muffler removed. All up its cost about $220, theres a little bit more power, not much but still noticable. The muffler removal cost $50 and it makes a good noise when under load, but cruising along you cant hear it, as in it sounds stock. You might want to check with your local Ford dealer, but the blokes at mine said that K&N filters do not void warranty, as Ford approve of them. Sam