I thought of this as i own two pairs if you run dual setup there would be no flex cause these forks both legs are the same.it has a blow off feature that eliminates burping the fork .http://www.avalanchedownhillracing.com/Marz/Marzocchi%20Shiver.htm
I'm not familiar with this Shiver cartridge and didn't really look at the link too much but I know Craig makes some pretty awesome stuff (I have a Avy in my Boxxer) and will work as advertised. Don't really know if two cartridges are necessary, seems like a throw back to the huck to flat era. It'll definitely be a huge upgrade to the HSCV cartridges and having one cartridge will drop some weight… Just not sure if you'll have to mod something for the spring in the empty leg.