Been lurking here for a while and finally registered.
Well, I have an '06 Silverado cc 3LT, 5.3 w/3.73s. Here's a list of mods...
Performance: S&B CAI, Flowmaster big block 50 series muffler SI/SO with 3" pipe and a 4" magnaflow tip ran just like stock, Wheatley tune... ordered 180* Jet t-stat and waiting on reply from OPT so that I can order a Trans-go HD2, vette servo, billet 4th servo, hardened sep. plate and aluminum 1-2 acc. piston.
Show mods: Esky handles, billet tailgate handle from JPCustoms.com with painted bezel, Carriage works billet grille (cut-out style), painted bow tie, Silver Star highs/lows, 4 High with fog headlight mod, 2" drop shackles, Joe Gibbs 20"s on General UHP Grabbers 285/50/20, painted brake calipers (red), 20% tint...need some 5% on the sun roof, esky platinum gauge cluster and esky platinum A/C vents.
I think that about covers it. Here's a few pics







2007 Sierra Denali, 6.2l L92, 6L80E, 3.42s, AWD, Outlaw CAI, 160* t-stat, magnaflow muffler and HPTuners!