I would assume that since all snow leapord is, is just a total intel version, meaning no PPC compatibility. That would not really be any major changes to the overall structure of the OS other than to remove UB and PPC. So assuming that, that is true, there would not be any reason to think that would be true. You can always buy a new hardrive and install Snow Leopard on that, thus keeping both versions, which is always a good idea. However I wouldn't make such a switch until all the bugs are worked out.