anyone have any links to studies done for the longevity of a tranny for differnet shift durations? specifically the 4l60e. my good friend says that the stock shift is the best for longevity, however, i beg to disagree, but since he works for a gm dealer, i know less than him. i want to do the larger servos and pcm tune. he says it all will break sooner. but i am on my 3rd tranny with 45k. any links helps.