Reflashing ECM and TCM

[87Skier]

Does anyone have recommendations for shops that reprogram the ECM and TCM for Gen IV engines and 6 speed automatics?

I've talked to a few shops but their responses to a few simple questions made me rethink sending my stuff to them.

Looking to keep the engine pretty much the way it is. The only modification is that I won't be running catalytic converters since it is emission exempt.

Also want to change a few things about the 6L80/90 transmission.


Thanks