I don't think most people track their S70s regularly, as there are many many better choices for that in the price range. But that doesn't mean people haven't done track days. I did a few in my Subie and think it is a worthwhile experience. It's a modification that makes you faster, no matter what you're driving ;-)
I want to hit Watkins Glen with mine. They have a session next month, but my car wont pass tech right now due to a broken rear spring in my KW coilovers. KW said eight weeks to get one from Germany....arrrggghhh.
I bet these cars will surprise many folks at the track. Im running the normal performance mods and a tune and have no problem taking Mustangs on the highway. Add in a my coilovers, sway bars, braces, etc and i think she'll do ok at the track. Hope to see some other unconventional cars out there with me!