Do a search for OST-Dyno on here. They picked up ~60whp AND tq with just an engine and trans tune. Rev limiter is bumped 500rpm, which helps get some extra power up top, as well.
I have been _very_ tempted to do the same... 180^ t-stat, PCM and TCM tune. But the warranty is gone (even if you swap the PCM back to the stocker... I believe dealer software can tell), so at that point, might as well do a pulley, at least and pick up another 40+whp/tq, right?
'18 Billet Silver Trackhawk
'02 Lingenfelter Twin Turbo Z06
'11 Corvette ZR1
'14 Audi SQ5