I need a good reason to throw on an aftermarket exhaust. Performance qualifies. Quiet is good, and lightweight is nice. To get all of those in one package is very difficult, especially when replacing a quiet stock system. Very few companies can go three for three. Leo Vince comes close with its $699 Ti CRF system. At 9.04 pounds, it is slightly more than ½ pound heavier than the stock CRF system. But the area where it really shines is the sound. At 91 decibels, it easily passes any public-land riding requirement. But the real-world sound, when you are tapped out running up a hill, is a moderate tone similar to the standard exhaust with the stock tip still installed. In fact, the intake noise is almost as loud!Installation was simple, and the fit was perfect. The pipe is very high-quality, with spectacular welds and tightly wrapped rivets complementing its constant taper design. The only picking point was the lack of a heat shield. The latest version has this covered, as well as carbon-fiber attachments and lighter weight. The header rides very high and makes getting to the kickstarter (not a problem on the X) a finger-burning experience if you aren’t careful.So how does it work? By complementing the CRF250X’s powerband just where it needs it the most. For best performance we bumped up the jetting a bit, going one richer on the pilot to a 42, plus a 135 main jet, and switching to a richer needle—NCVQ (part No. 16231-MEN-671) in the fourth position for just above sea-level riding. We didn’t open up the airbox, because the bike stays quieter and the filter stays clean longer.The pipe’s tone is deeper and more robust without being loud or sharp. Throttle response, especially when the bike is jetted properly, is crisp and a lot livelier. This translates to a better pull right from idle and, it seems, a significant improvement in torque on the bottom—where this 250 could use it the most. Through the middle, the bike feels about the same as stock; on top, there is a little more pull and less sign-off when approaching the rev limiter. Quick on-off throttle response is also better. It feels as if the bike has a bigger flywheel on the bottom but a lighter one when you need snap. There’s no difference in weight when riding, but your neighbors’ ears will appreciate the subdued sound.