Quite a bit actually. Saito has moved the vent connection to the front of the engine. I suspect they did this to provide a more positive flow of oil to the bearings ,and more importantly the cams and cam gear. There were a few bearing , lifter and cam gear failure that may have been headed off by this wise move.
If I had any of the older Saitos I would consider updating them to the newer arrangement. Jusy my experience Based on a few bad bearings and 1 very bad cam gear, As well as a few other engines that crossed our bench.