Welcome:). You ask tough questions and then want speedy service...this isn't a live-tech-support forum and no-one here gets paid...sometimes it takes a day or two for an answer to complex multi-part questions, so please be patient.
For your 166...have you tried to read some cds and dvds to see what speed they would read at(I am assuming you mean 'cd-rom' not 'dvd-rom' when you say 48x read speed)?
As for your kprobe scans, I think the BS0S scan is far better than the BS0C scan. That is a good burn particularly for those type of discs, which are inconsistent at best and usually poor quality. BS0S has by far fewer total PIF's and only PIF max of 2, and PIF totals and max's are the most important results to consider. They both have the PI mountain at the beginning which isn't good, but still within specs. Some picky players may have trouble with that section. The verbatim's should be better. Both GSC001 and MCC01GR20 are -R discs and Lite-ons usually prefer +R discs and +R discs can be bitset to read as dvd-rom booktype.
As for burn speed, you can try to enable 1x or 2x burn speed in OP(is the option there?), but I don't think the 1633 is capable of burn speeds under 4x and if you use good quality media, then the burns should be of good enough quality to work for your needs. I would recommend leaving the burn speed at 4x. If you are getting poor results, then you can consider a few other options like strat swap or better quality +R media.