I've not tried to mod the 83, 93, 103 but have an old Oppo DV980H which just involves a 4-digit code on the remote to toggle on and off. I only have one out of region DVD (have a few zero region ones that play on anything) and so for me I'm fine with the old 980. I've read that the 970 file hack also works for the 981. I bought my 980 new and at one point was going to sell it until I found the easy way to make it region free. I've read that this hack designed for the 83 works with the 93 but of course have not tried it - http://www.multi-reg...net/oppo_bdp-83
If you want to stay current with firmware, a hardware mod is the only way you're going to get region-free playback of Blu-rays on an Oppo (I think the earliest firmware of the BDP-80 and/or 83 allowed a software code, but that was disabled with future firmware releases).
You do not want to operate on out-dated firmware, IMO. I had a few problematic discs that the enhanced firmware fixed.
Now, if all you're after is region-free only for DVDs, then you can download the software file SuperDisk (which is what your above link points to). When I was troubleshooting a troublesome R2 DVD, Oppo themselves told me to Google and download the SuperDisk file and try using that for DVDs (instead of my hardware mod) to test it out.
So, Oppo themselves know about (and are okay with) a person using SuperDisk. Remember, though, that is for DVDs only, not Blu-rays. It also appears that the file is supposed to also be compatible with the 93 and 103.