I've had my SC 430 for a year now - the first thing i did with my car was change out the crappy hard run flats and go to a 20 inch custom wheel, this was done before i had 250 miles on the car. I went to a Zennetti 20 inch wheel and Bridgestone Potenza S03 245/35/ZR20 (the lower profile tire was used to compensate for the larger 20" Rims).
The car immediately looked awesome and you could tell just by looking that it was different. However I immediately had two other problems, first because of the hard side walls of the runflats putting on a soft - preformance tire made the ride absolutly to soft and the cornering was like trying to drive a big Lincoln or Caddy at Indy. Second because of the softness in the ride the car kept bottoming out and hitting the wheel wells. I resolved these problems by installing new supension i used "TEIN" off road shocks to get the disired ride and handeling i wanted (i drive half in canyons and half freeway).
I'm taking a chance with no spare but a can of quick fix is with me at all times and i have 18000 miles on my car.
Good Luck - Today i am a happy camper - it's worth the time and expense........
