I have a 15,000gvw dump truck with a 16 hp BillyGoat Vac. I saw a 23 hp BillyGoat at a trade show. It was way better than my 16 hp. The specs have about the same cfm, just a bigger diameter hose. I heard that some large vacs( Giant Vac) don't reduce the leaf volumm as much. I think that I want to build a swing hitch and put a LittleWonder 27 hp (claims their little blade thingy on the impeller reduces the leaf volumn) vac on it. I think a tow behind would be a pain backing up (like my chipper) and I back up a lot vacumming. Thanks for the input.