I got one used from a DT member ($250.00 shipped, woohoo!!!) and started with the 87 tune with the rev limit and shift points set pretty much like most others who have posted here. It made a very big difference, not so much in HP, but it nearly eliminated the torque management BS that the truck has, made it shift like you would expect an auto to shift consequently making the truck feel alot faster. I ran a few tanks and decided to fill up with 93 octane and give the 91 tune a rip. The truck sounded different and felt slower, so, I put it back to stock so that I could update it online. That's when you really notice it, when you put it back to stock after running with it tuned!!! Slow and crappy torque managed shifts!!! All went well with the online update and I am about to put the 87 tune back in, I just like it better than the 91 so far. Maybe if/when the intake and the exhaust are upgraded, it will be able to take better advantage of the 91 tune? I like it!