Aftermarkets Companys

I just recently bought a 1999 camaro z28 5.7 auto trans.
I would like to know which aftermarket company would/do you use an which one to use an which ones to stay away from I usually build c1500's an s10's I would like to build it for street/strip/autocross so any help would be greatly appreciated.
Which company's do you like best if I don't have your company you can add it.
UMI
BMR
HOTCHKIS
EIBACH
HAWKS