I haven't seen all of the available tunes out here, but I can tell you that even the RENNtech "intermediate" upgrade will completely transform the car. We frequently attend the Shift S3ctor airstrip events, and the RENNtech-tuned E63 is able to keep up with E63's with upgraded turbos (losing by 1-2 car lengths). Additionally, the same E63 with only a RENNtech intermediate tune recently went 11.04@130.89 at Famoso (500-1000 DA), full weight!