I have had great experience with Bob Piper at North Lake Tahoe Motorsports. I found him on ebay and have used him for OEM and aftermarket engine parts almost exclusively. Wossner pistons and all of the gaskets you would need. He takes requests, too, so you can ask for extra base gaskets, bearings, etc. He appears to have quite the stock, but I don't know if he is still a Gas Gas dealer since the restructure.