A set of 18-inch alloy wheels were standard for the M3, with the option of 19-inch alloys. Michelin Pilot Sport tyres were original fitment in 225/45 ZR18 front and 255/40 ZR18 rear, with the 19-inch wheels using 225/40 ZR19 and 255/35 ZR19 tyres front and rear respectively. The CSL has unique 19-inch alloy wheels with Michelin Pilot Sport Cup tyres in 235/35 ZR19 front and 265/30 ZR19 rear sizes.
Behind the wheels reside 325mm ventilated discs front and rear with ABS as standard. The power assisted rack and pinion steering of the standard M3 needs 3.2 turns from lock to lock, while the CSL quickened this with a 14.5:1 ratio rack for 3.0 turns between the stops.
Upgrading the brakes for track use is worthwhile and Pagid Yellow compound pads are a good first step. AP Racing's 335mm front discs with six-pot calipers are the next logical step for greater stopping power.
As with all E46 3 Series, the M3's front ball joints wear and spoil the feel of the car, but they are a straightforward repair. The front wishbone bushes and rear trailing arm bushes are also likely to need replacing on any car with 60,000 miles or more on the clock. Rear coil springs and dampers will most likely need replacing by 80,000 miles.
Aftermarket suspension kits are widely available for the M3, but cheap ones can ruin the ride and handling balance. Eibach or H&R springs are worthwhile, while AC Schnitzer kit is better still but expensive.
Last point to look for is a cracked boot floor. BMW will replace it for free on cars less than 10 years old, but it will be very expensive to fix on cars where no goodwill is offered.
"Only thing my M3 had of interest were the six-pot AP Racing calipers up front and the four pots on the rears - they are ace. Really good brakes."