I drove the central coast in a rented Mustang convertible for a few days several years ago, from SF down to Hearst Castle, and points in between, including back and forth from Big Sur to various destinations.
Like every male on the planet, I think I'm an above average driver. :)
But I have to say, there were locals driving anything and everything who were pushing my comfort zone a little. We were holding them up, and sometimes I pulled over on the turn-outs just to let them by. I'm sure they are used to being held back by tourists, though. If the passenger is squeamish, the northbound route would be preferable, because they'd be on the inland side.
edited to change to northbound. :S