I'd really like to do more events in the wet. We don't have many here - rain usually means thunder and lightning, and at that point we run for cover.
The MR2 is a lot of fun when it gets slippery. It's a challenge, but a lot of fun.
Chike's right, you're going to need to be extra smooth. I've never autocrossed my SVX, but I can imagine it plowing ferociously if you push it. As for setup, I haven't the faintest. On my MR2, I'd be inclined to soften the struts slightly, but not by much. I have my preferences depending on the surface we're using, so obviously I'd start from there. If the surface is extra-smooth, you can get away with a lot.