will this fit my blaster

I'm waiting on my 450R shock in the mail...should be here by Thursday. It should be softer than even the 450R simply based on the geometry with my extended swingarm. If somebody rode one with a stiff setup it must of been with the preload all the way sprung and the comp turned way up.

I'm not SURE, but I believe the 450R shock is just kind of an "updated" 400ex shock. I believe it is better as it appears to me that the rezzie is larger(about the largest difference) and it has protection of the valves better, but other than that, the mounts are the same, the 9.1" travel length is the same, Showa made both shocks, Adjustments are in the same location. The difference between the two are probably minimal when set up on a Blaster.
 
Just as a side note, a lot of shocks will fit up on the Blaster with a little work. I've seen a few others run the more uncommon LT450R rear shock and Kawi 450R rear shock as well. 250R rear will work. The shock just needs to be narrow enough to fit between the shock bolt up area with a tid bit of play and be realistic in terms of ride height.