I am sure that TEA and AI have good cnc programs for the 5.3 heads. I personally do not have experience with them and have heard good things.
I do have experience with PRC 5.3 heads. I have the 2.5 5.3 heads that TSP sells and on the head swap alone I gained 38rwhp and 30rwtq. My numbers are in my sig. My vote goes to PRC especially for the price.
02 SS T-56 523rwhp totaled on 2-18-14
New Ride: 03 Z06 455rwhp 445rwtq