Actually, a good question. Usually can't hear it in our cars.
IMO, setting the timing per JoeMag is the way to do it - this is why setting the timing on an engine dyno or loadable dyno is the best way to tune. I'm fortunate to have the spec form the prior build - derived from the engine dyno in 2004.
3.4L, SC heads, 964 cams, B&B headers, K27 HF ZC turbo, Ruf IC. WUR & RPM switch, IA fuel head, Zork, G50/50 5 speed. 438 RWHP / 413 RWTQ -
"930 is the wild slut you sleep with who tries to kill you every time you "get it on" - Quote by Gabe
Movie: 930 on the dyno