History has proven that stock Honda 4 stroke exhausts are hard to beat on the dyno for an overall package of power, quietness, and durability. I remember the 400EX dyno shootout where the FMF exhaust actually made LESS hp than stock. I've had a few 250SX's with Bassani exhausts, very cool sounding and a slight more top end hp if you really wrung out the rpms. Still the coolness factor of these old exhausts worth it for a conversational piece.