Based on a recommendation from Rob @ Gearheadz, I took the Z down to Mad Hatter and had a new exhaust put on. 3" from the collector into flowmaster 40 series. It took forever, but the quality of work was well worth it. The car just came alive with the 3" pipes. Definitely more pep in it's step. Sounds mean as PHOK.
http://i47.photobucket.com/albums/f194/transamdrag98/P1040058.jpg