I do not have a GF at the moment, but would not hesitate to let one drive ANY car, if she was a decent driver. Here in L.A., it is an every day occurance to see women driving 911's, including the fastest ones ever made. 99% of the time it is testosterone that wraps sports cars around trees. (Often mixed w/ alcohol, of course).
I am most hesitant to let other men drive my car, would have to remind them not to beat on it, "it's not yours." 911's of course drive a little differently than other cars, not a big deal if you take it easy at first- the way all good drivers begin in an unfamiliar car, (or one that you do not own). I used to work at Porsche dealer and give test-drives in 911's; the world is absolutely filled w/ horrible men drivers- ham-fisted, bull-in-a-chinashop, no sense of "touch", total idiots behind the wheel and think they are good. Women drivers on the other hand are either complete ding-bats or very good drivers, and much more likely to take it easy in an unfamiliar car. My .02.
