I made the mistake of having a B&M shift kit installed in my 30k stock trans a few years ago and the trans never worked correctly since. i replaced it with a trans from Brian Hofer and have been very pleased since:smile: .
He is old school. doesnt sell kits just trannys. he uses the wide bands machines his servos and covers down (case stretcher) and drills the lavebody fluid passages.
Really a shift kit is just getting the fluid to move faster. you need to take your valve body apart and drill out certain passages to certain sizes.
Have I would guess 1000 passes on my Dynotech trans and still shifts fine... Firm shifts, but not like some of the skiftkits where you'd almost piss blood.
Last shift kit I did was a Transgo for a TH350. All I did was replace the springs in the valve body and swap out the seperator plates. Shifts were firm but not jerky.
I did have a B&M in a TH350 in an S-10 once, would bark the tires in 2nd, and chirp them in 3rd. I always thought that was cool. Until I learned that's actually bad on the sprag.