Just thought I'd throw this out there....
Test rode a 350-SXF today... Was an absolute blast, what's funny though it reminds me of a heavy 2 stroke... You really have to wring it just as hard as the 250Fs/ 2 strokes to get anything out of it, can't really ride it like a 450 (something that it was claimed you could do with it) though. All the power it in the top, but I suppose you could lug it around (didn't do it). I was on the limiter probably as much as I was riding the 250Fs.
They really should move the 450s to 350s. So much more fun to ride (and easier to ride faster than a 450), and on par I think with the 250 2 strokes (much more so than the 450s). Too bad that it'll be as rebuild prone as the 250Fs though.