I read on page 146 of the owners manual Winter tyres, front 18inch, 225/40, rear 18 inch 225/40. Could any one explain to me why the departure from the standard tyre/ wheel set up? I am curious as to why. I purchased my 04 coupe with 20 inch after market wheels with 245/30 tyres with an off set of 35mm all round- which means I can fit any wheel to front or rear . Over 90k the steering wheel shakes indicating out of balance, I have since put the 2 front tyres to the rear, fitted new tyres to the front, had all the wheels balanced, still shake , took car back and rebalanced again, still shakes. Eventually was told by tyre company that any one who fits 20 inch wheels with low profile tyres is a -----! worst wheel ever fitted to a vehicle, may look good but that's all. I am to the opinion they are correct. so hence the fitting of 18 inch wheels to rear. Probable improve the ride slightly , could effect the tail road holding, although I have on a couple of occasions felt the rear hopping an rough corners, which could be caused by the very low profile tyres having very little give on the side walls. What's your thoughts? Saltiga