As good as a stock E92 M3 is, one modification that can increase horsepower by a significant figure as well as improve sound, among other things, is an exhaust system. However, choosing the right exhaust system is usually a challenge. For some, an aggressive exhaust note is the only priority, but when it comes down to choosing an exhaust system there are actually many factors a buyer can consider. On a sportier vehicle, weight savings is typically a goal. With that said, higher performance exhaust systems are made of various materials like stainless steel, aluminized steel, titanium, and even now nickel, chromium, Inconel, and other super alloy materials. Other factors of the exhaust systems would be how restrictive the system is, whether the system is a full one or just various parts, and perhaps the most critical of all, cost.