i just took a look at your post, i'd say i agree that it's better to own the physical media, as hardrives are increasingly unreliable today, i have more than 12 6TB drives that have nothing but JAV and a alias database. all of them have a lifespan of less than 3 years, which is when a chkdsk often report bad sectors. even when recovered, files tend to pixelate due to data corruption and zero overlaps.
i had to travel to JP for work on and off, so i buy stuff in bulk and send them back home.
the DRM hangup of DMM and R18 can be easily overcome though, if you have a desktop that is at least duo core, and 8+ gigs of RAM, you can just do a video capture with Adobe Premiere or Adobe Captivate. just make sure you check the original file's FPS and bitrate and adjust accordingly.