Welcome to the new and improved Proflex / K2 Tech Forum!
So where on earth did you find such a spring? I've looked all over...the "Proflex" Ti springs on US eBay actually work fine as Vector/Crosslink front springs for me, but I've never found anything appropriate for the rear. How 'bout this...I put you on an exercise program and you sell me the 600 lb spring? ;-) LOL- Doug :-)