The S58 engine powering the modern M4 is renowned for its robust factory bottom end, but pushing into big-turbo horsepower figures requires a reinforced internal architecture to handle extreme cylinder pressures safely. Fortify your block using high-strength Forged Pistons and heavy-duty Forged Connecting Rods/Conrods. Secure your rotating assembly with high-tensile Upgraded Engine Bolts (ARP) and minimize internal drag using race-specification Performance Bearings (Conrod & Mains). Ensure a complete, leak-free seal under massive boost using heavy-duty Engine Gaskets, and maximize volumetric efficiency with Performance Camshafts and Valve Spring Upgrades.