My wife has autocrossed with me a few times, and when we get serious into it, is also planning to run. I was really surprised how hard she pushed the car the first time out. We're planning on doing the evolution schools too. I'll probably due phase 1, then let her do phase one the next time it comes around. I figure it would be too hard (if not impossible) to have 2 people running one car during the school.
She won't drag race though, that's ok though, cause you can get into trouble pretty quick there if you don't know what you're doing and how to react (miss shift, fishtail, etc.) Autocrossing, about the worst you'll do is hit a cone or do a little offroading.
Right now she's not real keen on me doing a road course, but that won't stop me

I don't know if I'll ever get her to get into the drivers seat though.
She also tolerates my mods to the car and truck. I somehow have convinced her that she wants a 70 Chevelle SS. I mean I can't complain, and who am I to say "NO" to her when that's what she wants.

I have explained to her that the Chevelle would be after my 68 Camaro.
Oh, BTW, she does have a sister