Anyone tried upgrading a TBI engine to EFI?

[Mackman]

Hello, I am new to this site. I am hoping to gain some knowledge from others that may have achieved upgrading their TBI engine to one of the new EFI systems such as the Holley Terminator, FiTech, FAST or E-Street 2? I am thinking that this would be an improved system over the factory GM TBI. I am confused on how the transmission would react to these systems or if a transmission controller would have to be utilized. Any info would be appriciated.