i runing a glh clone 2.5 turbo 14 psi.250hp est. The car is gutted and caged i currently have 525 with a welded diff 3.50 gears great for ice racing not great for the street , I have two 520 's with one a3.50 the other 3.85 which would be better with the power i have and wheight 1/4 mile and street and autocross?