I own some. Mostly bought them on some random sex shop when i go to japan.
I own STAR-134, CHNS-004, MIGD-347, MIDD-599, STAR-165, MIMK-007, TYOD-145. None of them are particuarly special except for the fact that they are some of her early work, but i like the souvenir.
I don´t think i can recommend getting second hand DVD from before 2010 since they are starting to go bad. The japanese are known to take good care of their stuff, but you are buying an almost 20 years old disk without confirmation it works.