As mentioned above, got one of those as well as a complete intercooler kit on the way. It really doesn't roll coal unless I punch it at half throttle while in neutral. I have a habit of starting off from a stop in second and still don't puff. I have noticed that even leadfooting around I never notice coal unless I am not paying attention to what gear I'm in at a stop sign/ light and start off in 3rd. Then there's a large plume of coal for a second till I realize my stupidity and drop a gear and take off. Either way, as soon as the turbos and intercooler kit gets here I'm putting those on and the arp headstuds and I hope my fuel mileage stays close to the same or better. Alot of extra power makes it hard not to use it which in return will burn up some of my mpg. Been going easy on this tank of fuel and taking forever to burn a tank of fuel up, but that should mean I have really good mpg. We will see