Finally got one with mine... it's not the greatest, I'll have to update it when the motor's fully broken in.
Stock Vortec long block, GMPP intake (PN 12366573), Edelbrock 600 (1405), Comp XE268H cam (12-242-2).
Hooker 2451 headers, 2½" Pypes full G-Body exhaust with GN-style exit, X-Pipe, and RacePro mufflers. It's much quieter than I expected, instead of being obnoxiously loud, it's surprisingly docile-sounding & deep at idle inside (mic didn't really pic it up on the mic). Cruise speed still has a bit of resonance, and on acceleration it sounds vaguely similar to a mod-motor Mustang.
http://www.youtube.com/watch?v=-gJe9i96OFM