whats the difference between high compression and low compression heads? Also what type of gears should i put in my 2000 Mustang GT 5spd? I am going to go turbo so i wanted to get everyones opinion because i have just got into performance cars for about 4 months now...what does everyone think? Also will a hypertech Powerprogrammer III work for tuning the gears ect...or should i go with diablo or another brand?