James, Jimbo bought my 35i and changed the. Runflats to normal, and. Immediately he said the car was much much better,
Tim I disagree with you, re the warranty. On the Z4 they can and will say the warranty is void to anything related to wheels and suspension.....no hesitation. You'd have to argue the toss with them until you're blue in the face, as the car has been modified. You can protest this, but believe me, BMW would stand their ground and would win.
I'm not sure many new E89 owners would go straight to standard rubber....but who knows