Any decent LHS should have one... if not, then check at tower hobbies and do a search or any other online hobby shop. They definitely don't make the engine quiet, but they do knock down the sound a little bit... and I mean a little, not too much. As far as performance, they don't add anything, they may add a tad bit of backpressure because of the extra length, but nothing notable. As far as keeping the vehicle cleaner, oh man... BIG time. I will never run without one again. It really makes a difference.