http://c3riders.freeforums.org/07-c3-custom-progress-t304-10.html#p3289 This guy lower it . After looking at pictures of the frame I don't see what you couldn't Raise the rear tub up with shims to help the leg room for tall guys. The rear tube is held on with 4 bolts or so. that bolts onto the frame. Seem like a couple peace of drill out square tubing and your good to go with extra leg room. Am I wrong? Here a 3rd picture of a japan c3 custom to give you an idea of frame .