First off, I am new here, but have been around on the other powerstroke forums for a few years now. I was very hesistant to buy aftermarket tunes because I heard of the harsh shifting/bucking/surging etc... that everyone was having. I read a post about Gearhead tuning and called and spoke to them. After explaining my bolt on mods I got my emailed tunes and all I can say is WOW! I am currently on the Street tune but I have all the way up to the Race. This thing shifts like a stock truck but when you roll into it hold on! it becomes a beast! and this is on Street, I can only imagine what the other files unleash! thanks so much for the awesome support of the military, you guys make me proud to serve you. I just wanted to let everyone know that I will send all my 6.4 powerstroke friends to you. Your customer service was and is second to none and your tuning is stellar. My wife can drive this thing and not know its tuned thats how civilized this thing is! thanks again guys you F*ckin Rock!!