Monster transmission
but a better question would be who you should do business with and a brief time seeing advice given in the threads in here will give you the major players , there are several reputable shops that are sponsors here and you can see the ones that spend a lot of time on this forum helping people make good decisions , that is customer service those are the guys you want to do business with.
I am avoiding mentioning names because I haven't personally done business with any of them but from seeing who is helpful & knowledgeable on here I know the shops that I would consider.

