I just rebuilt my Sachs too. Another source for parts in Handy Bikes in Ohio. Do a google search for "Handy Bikes". Their webpage is slim, but they have a great selection of Sachs parts at great prices. They used to be the US distributor for Sachs.
You might open up the engine/trans before ordering parts.. my rings were fine, so all I really needed were gaskets (order a complete gasket set for $14) and an plastic oil-plug. I also had to get the plastic side-panels for the bike, a few switches, tires/tubes, etc.
Good luck w/ it. Mike bartell (mbartell) posts alot on this forum, and he's just redone his Sachs too. He was a big help to me when I was doing mine.