As I get closer to making this 3 wheeled thing happen for me I'm finidng I have more questions than answers. First, I love 2WD Urals, but have serious concerns with on-road preformance - particularly up hills. Which brings me to wondering about the weight of the tub. Yeah. I know...this will sound foolhardy to many. I know Claude and Jay make thier tubs from aluminum and fiberglass, respectively. How much weight savings would there be from switching the factory steel tub for either of the well known and respected ones mentioned? And this kinda brings my rambling thoughts to a similar issue; If I don't go with Ural, the most likely alternative would be to use an '07 Bonnie for a tug, with the option of using my '07 GS a very close 3rd. Used Ural tubs are fairly easy to find, and (I'm guessing)much cheaper than a one-off custom from CSM or DMC, and the weight difference might again play a role in decision making. The other issue is sub-frames. Perhaps this question would be best directed at the pro builders, but many have done thier own and I prefer to have a hand in at least setting up my own. What IS a subframe? Don't the chair mounts attach directly to the bike frame? If I find a Ural tub, can I buy mounts from Jay and hook it right up to the '07 Bonnie? Or does it need a subframe? What about buying the whole set-up from Claude or jay? Would "sub frame" be an option, or part of the package? And speaking of "the whole package", would I save that much by useing a Ural tub, or would it make sense to just do the whole thing? What about the '07 GS - same questions...subframe, heavier vs lighter?