I agree with Tony - I'd start with the castor bushes as well - they can only help with the standard wheels too if you do go back to them in the end.
I think it's fair to say most people agree that 17's is the best compromise (provided they are light) - the 968 CS, generally thought of as the best handling of the breed, had 17's after all... So says Mr set of 16's and set of 18's
I think it's fair to say most people agree that 17's is the best compromise (provided they are light) - the 968 CS, generally thought of as the best handling of the breed, had 17's after all... So says Mr set of 16's and set of 18's