Replacing the rod bearings on the S55 engine in the F80/F82 M3 and M4 is an important preventative measure to ensure long-term engine reliability and performance. While the S55 is a more modern, turbocharged inline-six compared to its predecessors, it is still prone to rod bearing wear, particularly in cars that experience aggressive driving, track use, or higher mileage. As the bearings degrade over time, they can lead to reduced oil pressure, increased friction, and ultimately, bearing failure, which can cause significant engine damage. The S55’s turbocharged nature puts additional stress on the engine internals, making it even more important to monitor and replace the rod bearings as part of regular maintenance (typically around 60,000 to 80,000 miles, depending on usage). Replacing the bearings proactively can help avoid expensive repairs, prevent catastrophic engine failure, and maintain the engine’s performance, smoothness, and longevity, making it a smart investment for any F80/F82 owner who values the reliability and driving experience of their M3 or M4.