Your best bet is looking on m3 forum for a car being turned into track car. They sell all those pieces since they don't need them. But still might be hard to come by.
You can order the miscellanous pieces from tischer I guess.
Car for sale http://www.e90post.com/forums/showthread.php?t=881526
JB4 G5 - Forge FMIC - VRSF V2 DP - Magnaflow 15529 Catback Exhaust - BMS Clutch Stop - BMS DCI - CDV Delete - Dinan Stage 3 Suspension - 19x8.5/10 Forgestar F14 Gloss Gunmetal - Michelin PSS - M-Sport Front & Rear - M3 Side Skirts - OEM M3 Decklid Spoiler - BMW Performance Grilles - ZHP Shift Knob - M-Sport Steering Wheel - M-Sport Door Sills