A few thoughts: 1) the new 250/300 (since 04) is fantastic. Less vibes, same great reliablity, snappier power. It's based on the 03 250sx motor... 2) I don't ride MX much (if at all) on anything... but the 300 is pretty smooth in how it delivers it's power, which may not always be advantageous on the track. The suspension on the EXC is also very soft... which obviously can be easily rectified with springs and valving. 3) Since getting the 525, I'm even more enamored of the lack of maintenance required by the chainsaws. No oil filters to buy, no valves to adjust- just stay after the air filter and tranny oil, and ride the hell out of it.