I got my answer. The Kubota rep called today and confirmed that the loader would be fully warrantied with the tractor. Apparantly the BX series carry the same frame/subframe the only difference is the tires and the HP. He did recommend additional ballast, which I do plan to add. His feeling was that the dealer was upgrading my loader as a convenience to not delay delivery, and him not having to order a 203. He added that the loader arms are the same, the difference is in the cylinders and the bucket. I guess i'll take the upgrade, fully warrantied and enjoy it. Thanks for all your responses and info. It was very helpful for a new tractor owner.