The M4's engine brace, trunk lid and the roof are all made of Carbon Fiber Reinforced Plastic (CFRP) to shed pounds. But the real masterpiece for both is the CFRP driveshaft — a one-piece unit that offers exceptional strength while reducing rotating mass, resulting in a tighter drive with less counteractive momentum. This cornering king's real crown is its rear-axle subframe with solid mounts, bolted directly to the body without the use of bushings to make for the…