I got burned on one of the Japan LD's. The sound quality was poor as well. The 20th anniversary version is not what we want. That has the remix from hell.
This PAL version should have Digital Sound.
http://www.lddb.com/laserdisc/34199/21.04.002/Grease-%281978%29
http://www.ebay.com/itm/361138231715
The obvious problem is I don't have a PAL LD player.
JEDIT: Here's another one.