I started out with a mild 390 with stock (burned out) glasspacks and it was kinda loud and raspy. When I went with my nasty big block it got to be *real* loud and raspy. My next door neighbor looked at me like she was going to hurt me when I wasn't looking.
Reluctantly I changed over to 24" Race LoBaks and those funny little cones. A little quieter and less raspy. That's as good as it gets. I still use my ear plugs, but if I forget them on a short trip for breakfast, my ears aren't ringing when I get there.
I plan on running the autocross at Sears Point for SAAC 35, but will be real hurt if I get black flagged. I *might* consider the track, but am afraid my beast is faster than I am. We'll see. Rich