Wow! Get ready for a flat in about 5 minutes! And a loud and bumpy ride. You're talking a profile of 2" or slightly less on a 4,600# car. Probably air pressure close to 50, easy. And expect your tread to last for just about nothing. I have 21's on my RWD and can't get more then 9K out of the rears (lead foot), 19K in the front. Boy I love the look. I if I had to do it over again, I might have done it differently. I have thought about new 20" rims. But I really do love the cyclones on my car. I haven't found anything I like better.
And living in SoCal, you know how the roads can be after it rains. I drive gingerly to get around the rain-induced mega potholes that show up overnight! They are about the same in Santa Cruz as they are down south.
Just sayin'. And congrats on the car. You will be more in love every day. 3 years in and I love my girl now more than day one!