Oh wow - this belt size chart is AMAZING! And yes, the Gates site for belt sizing is definitely "awkward" to say the least. You're a life saver, Bro. Much appreciated!
Yeah finding the correct belt size for this combo is definitely a travesty LOL. It seems that the 594HD will work best - as the 3.17 isn't much smaller than the stock 3.35. Some have also gone with the additional adjustable idler for added protection against possible belt slip. I just installed the Incog lower last month with ECM/TCM tuning from Dusterhoff. I got the full 2psi as advertised and great tuning. Couldn't be happier with the results thus far. My boost gauge consistently holds at13psi with brief hits at 14. Just ordered the 3.17, FIC 1000s and a few other supporting mods a few days ago. But probably won't be able to get started until after the New Year. Should be a little over 15psi when finished. Hoping for a minimum of 730-750 to the wheels. I'm staying on pump gas for the time being, but left some headway to potentially add a Flex fuel setup later on. But yeah, I'll definitely keep you all posted along the way 😎