Original M1 racing version cars (Procar) were all turbocharged. So ... Don't mix a standard engine with the M one. 335i / 135i etc is not a racing track car. 335is is closer to that - more modified for track environment. Stock 35i is not - it wasn't the aim of 35i to be a race / track car. While M FI engines are designed to last on a track as well. M1, M3, M5, M6 ... (and even X5M / X6M) will prove that. Not only the joy is futureproof, it's also techproof. Joy is BMW. Regardless the time, regardless the tech, regardless the shape.