I gotta say for flatwater it comes down to what you consider a backflip, yes a 850cc ski will backflip... But your not getting big height with the XFS /XFR with small motors & most guys just get the nose in with smaller motors. Still a flip, but to me a flip is plate to plate for flatwater.... You can get big height on the XFS but its no trim backflips which take some brap under the hood... Gotta remember the Rickters have a lot of weight to be flipping, I'm sure the Bob is a lot lighter and I know the freaks are...