I highly recommend the Kumho SPT to any SoCal resident. This is a summer tire and is very quiet on all road surfaces. I spend time on the 405,5, 10, 15 and 215 fwys in quiet bliss. Very smooth ride and grab like crazy when cornering at speed. I'm running 225x40x18 on the front and 275x35x19 on the rear. They are ok on wet streets as long as you take reasonable care. Stay away from Ice and snow. The larger tires on the rear have plenty of room and add real stability to the handling of my XF. I have a 2004 6spd coupe.
If you have any other questions give me a call. (619)276-5462. I'm in San Diego.