I bought one of these & have a pretty good tune going (but I'm sure it can be made a fair bit faster). I did the RM, ECU, stage 2 eng, intake & race filter, cat, exh piping, hard race tyres & LSD. I'm not sure if some of that comes with RM as I did it a few days back. I dropped the susp as low as it can go, added a notch to the rear rollbar & added 2.0 camber at the front. I think the LSD is set at 20/45/15 in that order & tranny set to 300kph. Give this a crack & see how you go. Should be something like 455hp & 1085kg. If the handling is still a little off for you, play with the front & rear toe but only in 2s or 3s (more will ruin the extra turn from the rear rollbar).