suggest you stay with your existing 4L60 then upgrade with 4L80 components (adapter and output shaft).
You can use the same computer & harness you have. There is a pin-out mod for the harness.
CD, I have been told the 4L60 upgraded with OEM 4L80 would suffice what you and I want. Dependable. trail rig, no buggy stuff. Able to maintain modern urban traffic.
Let me know if you hear differently.