This MagnaFlow exhaust system is perfect for BMW owners who love taking long drives or weekend cruises. It's designed for 1987 - 1991 2.5L BMWs. The main piping is 2.25 inches in diameter and it has a straight - through muffler with 3 - inch polished welded - on double - wall angle - cut folded - edge tips. It's made of durable stainless steel, so it can handle a lot of wear and tear. And with its easy - to - install design, you can quickly upgrade your car and enjoy a more powerful and resonant exhaust note.