I've autox=ed my wagon, as well as a 2nd gen wagon. The best advice I ever got was to drive it like ti was stolen. It helps if you leave the roof rack and snow tires on, too. :-)
Look up iggydawg, he's hardcore autox out here. Helps with the club, instructs, etc. There's one more day, I believe, on Oct 20. Take your car as is, go run. You'll hvae fun. Ride in everyone else's car, too.
A stock wagon has a lot of sway and body roll. However, its the outside front tire that gets flogged. You'll never get enough tire to stay in class to make up for it. OTOH, there's nothing like a wagon posting in the top 10 for FTOD.
Look up for motorsports forum. There are lots of autox ppl there. Whitetiger, driftmotion, frank_ster, wpmarky, and many others I've forgotten win championships year after year driving legacies in autox.
If you get bored with autox, there's lots of track driving options, too. Just stay away from ryangt, as he attracts drama like bees to honey.