I just installed it in my 02 auto-GT, and I know it made a difference. I cant compare the shifting to the jerry-mod (never had it), but it does shift faster and firmer. It adjusted my rev limter to 6250 as well so I can put in those 4:10s this wkend!!!!!!!!!!! The hypertune is programmed for 93 oct gas, but we only have 92 in HI, dont know if I should put it back to stock tuning or not. noticed a little pinging at WOT but doesnt sound bad. Anyway, happy with it in general. Any other happy people out ther with the hypertech?