MR2's are weak and look awful. I almost said a car like those old school stacked Camaros, but I wanted to be a little realistic. Still, the muscle car would be awesome too, just for the irony factor like you said, plus, anyone who drives anything at all would love to have a sweet ride like that. Everyone wants to haul a little ass every now and then, even 4'8'' little girls like Kona.
I considered a lifted Silverado or something too, but if her hair were to be caught in the door (which is very possible due to its almost ridiculous length) she'd be hanging there until someone could get her down. It's still fun to imagine, though! :)