300ex shock

The 400ex shock has a better dampening rate, and is also tweakable with the adjustments.

In other words, a smoother ride

Not sure that anyone on here is running a 300ex one though
 
300ex shocks suck... and I have never heard of anyone running them on a blaster.

but 400ex/z400 shocks are awesome...
 
Huge improvement . I think the 300ex shock is a bit shorter. Would probably be good to lower your Blaster for flat track racing.