The twin spar was a real WTF moment that alienated a lot of Cat riders. On the heels of the lightest, fastest, and sexiest sleds on snow, the Firecat, they did a complete 180 and made the heaviest, slowest, and ugliest units out there (yes, I know they were comfy). Guys began jumping ship to the far lighter and better looking XPs and IQs of the time. An agonizing 4 years later we got the Procross, a unit that ironically was released far too early and way too cheap. It wasn't until the 14s hit the snow that it was finally the great sled it should always have been.
I can't help but think how different things would be if Cat had managed to release a finished Procross (2014+) back in 2007 and skipped the twin spar entirely *sigh*