Fits perfectly on my 2006 F250 Cockpit, 6.5ft Bed, 4x4, 5.4, 3v. Sand/broach to fit better. It's INSTANTLY a bit lively at 2K rpm, but PERFECT in everything else. It's not annoying or obnoxiously loud, but it makes more noise than a stick and has a very pleasant sound. I would recommend this as an easy to install, good value, quality stainless steel system that offers a little more exhaust fun than stock. You won't feel any difference in performance and I haven't noticed any increase in mileage. But I don't expect a 3/4 ton 4x4 truck to be anything but a hungry pig when it comes to fuel.