I have an 89 trans am with the 350ci. Already have changed all fluids, new spark plug wires, cap, spark plugs, battery. I plan on this spring to have done to the car is: slp runners, slp headers(4-1 power flow), holley throttle body 52mm, custom cold air intake, new high flow cats with a 40 series flowmaster muffler. 3inch pipe the whole way. I have to have cats and muffler where I live, because they do check that any idea on what kinda gains I can expect of a stock t/a?

With a close-to-stock engine, I wouldn't bother to upgrade the throttle body. The stock one will be fine.