There's nothing in it, my mate has gone to bike carbs, and has nothing good to say about the Webers he had before them... As for jet sizes, I'm sure Weber jets fit in R1 carbs anyway, otherwise you can just drill out whatever comes in the carbs (as I'll be doing) How could they be straight? They have to match up to the bike carb spacing... It's not ideal, but it's not the worst solution in the world for the difference in price to getting a full custom manifold made!