Most quality muffler/systems for BMWs (ie. Remus, Rogue Engineering, Supersprint, B&B) arent very cheap. If your looking for just a muffler, Id stay away from the canister style like the Weapon- R and go more for somthing like an oval style muffler with dual tips or somthing. Look into Magnaflow, and see what they have, they have all styles of mufflers and there fairly inexpensive....