[LarThaL]

You can just go to the 285/30 rears and keep the 245/30 fronts. In fact, this will give you exactly the same rolling diameter and shouldn't be as upsetting to the DSC as going to 255/35 front & 285/30 rear. Alternatively, you can go with 255 front and 295/30 rear as well. These will fit just fine on the stock 359 wheels, will give you equal front/rear rolling diameters and will only decrease the rear diameter by 8.5mm. The tires do then start to add weight however.

It seems to me that the M3 really should have come with wider rubber to begin with. Does anyone have any insight into why the stock sizes were chosen? They clearly do not provide enough grip given how much the DSC kicks in.