Id actually suggest the Diablo InTune cause thats what I used on my XK and have it on my Ram now, its night and day difference on both vehicles. Ive got better mpgs and much better performance, but I feel it cause I drive that way!!! When I drove from NY on stock tune all highway I was avg 14.8, on my last trip to Darlington for the race I got 17.9 doing the same speeds, so thats quite the bump for my truck. The XK was only 1.5-2 mpgs but the throttle boaster and performance was a big difference. It had a lot of adjustable parameters that I liked as well.. either way definitely worth the moneysssss