It's not a mod that I would put on the top of my list. It'll yield you an extra few ponies, but don't expect huge results.
P&P'd TB goes for ~ $150+
Personally, I don't buy the above claims (no offense, I just don't think it's realistic). If you go with a FAST LSX intake and 90mm TB you might yield 12hp. Most only show those gains if they're running FI or H/C.