So, this is pretty delayed on my part, but did want to check back in for anyone who may care/run into the same issues I was having passing HDCP through the 665 out of an HTPC.
As mentioned earlier in the thread, I was getting HDCP errors when trying to play back any retail Blu-ray discs (think my posts were around page 15?)
After some troubleshooting, I decided to simply take the advice of rdgrimes and use AnyDVD - this worked of course.
I have not yet tried updating my firmware but plan to in the near future to take advantage of remapping it offers. Once done, I will test again just in case this makes any difference in my results.
Thanks again to the great support community here at AVS!