To any of you that auto-x your alero's what all have you done to them? Or what would you suggest doing to the alero before auto-x'ing it?

upgrade suspension, sway bars and STB's, wouldn't hurt to upgrade your brakes either and some good sticky tires

stay smaller diameter with your wheels/tires. 16's or 17's max for auto-x. 18's or up and you're gonna loose low end torque to the ground. If I was going to auto-x my big 4-door tug-boat, I'd use my factory 15's for that and put on some 18's for cruisin or show.

Also, make sure whatever mods you do for performance increases low-mid range rather than high end.

sway's, STB's, coilover's, bad ass tires...........hmm all ican think of

The class you compete in dictates what mods you can do to your car. As you do more mods, you are bumped into higher classes - the cars are much faster, making it extremely difficult to be competitive.
Example: I could never be competitive in autocross the way my car is set up; I'd be up against modified Vettes and other cars that are tuned to the hilt.

BUT there's one minor detail there. I know I've seen some modified cars in SM and such that just don't have good drivers, so it could be easier than you think.