As a suggestion, contact each of the below folks:
Greg Peak @
http://www.dirtrides.com/
Billy Holt @
http://www.wrhracing.com
Dave @
http://www.bncracing.com/
Folks @
http://www.hetrickracing.com/
* They check their email and voices messages often.
Each of these folks are specialized in Performance upgrades on each of these brands. During your inquire, ask what parts most people upgrade (due to breakage or needed improvements) and which ones they sponsor.
Also, don't forget to fully describe your unique riding conditions. For example, deep water, trail, racing, dust only etc. Each brand has their own weak spot - based on where and how its going to be used.
Hope this helps as well...
.