Hey, nice to see another Alero owner here
You can start out with the threads posted in this section and the general performance section. You should be able to find some info.
The following web page is under construction at the moment but contains lots of useful information regarding alero mods:
http://www.aleroupgrades.com/ << the owner of the site is "Grouch" (admin for aleromod.com) and is in the process of upgrading the site.
Here are the threads that should interest you most:
http://invision.aleromod.com/index.php?showtopic=292
http://invision.aleromod.com/index.php?showtopic=1094
I've heard the Dynomax Super Turbo muffler and it doesn't sound ricey (as all who have it have said the same), but the rumble isn't much (it's only a 4 cyl
).
I know some people who have custom set ups as well, one guy here in the peg (chicken_dog) has his custom made and it rumbles much better than the dynomax (no ricey sounds either).