These things can be done in nearly any order as the $$$ become available... BUT .. even with no tune, my car would scrabble. Not just from a dead stop launch, but in first and also in second gear IF I was really nailing it. The Cobb AP removes the hp limit in those gears, so the effect (would be, I never had the Cobb, jut the mountune 215) even worse... . .. an LSD would help, but I personally don't want to spend that kind of $$$. The RMM fixed it.