Thank you Dave for the link!
Contacted a local guy who comes highly recommended.
He won't tune any cars that get emissions tested.
I guess CA is cracking down on modified vehicles which puts me...

Like reading the knowledge base you have here!

'99 GMC Suburban C1500 5.7L
4L60E took a dump.
gearing up for 4L80E swap.
Sourced parts already (rebuilt trans, new TC, spline, adapter harness,...