Hey,

While it looks very similar to the MAC engine (which is a "not for export" MDS), it is in fact an East German version of the same engine. The differences are slight but include the anodized head, the oval instead of the MAC logo and the different shape of the mounting lugs. (Take a better look flypaper). These are much rarer than the russian engine which is easily obtainable. The internal parts interchange, so that should not be a problem. As to perfromance, They are heavy, but perform as well as many current ABC engines coming out of China. They just look crude.

Max

P.S. let me know if you need a MAC pic for comparison as I have a few of them.
Don't know why you don't like MDS, but that is another discussion!