I will pass your greetings onto Tony, Jim.
To answer your questions
The speed issue - the UC6 Gold and the RCP80 rip small uncomplicated print files are very similar. However, if you take a more comlicated file (not uncommon in the print industry) for example CorelDraw sample file "Huntress.cdr", the UC6 Gold outputs in under half the time. This is as a result of the far higher speed processor in the UC6 Gold.
The line frequency - I have had reports that despite setting the line frequency and angles in the application (Pagemaker) and ripping to the RCP80, the result when viewed under a loop are incorrect.
Second pass registration - Like any mulit-pass printing machine registration is not perfect however this is not difficult to overcome (trapping, overprinting) and as I understand firmware updates are underway which will improve the TCII second pass registration.
Sequence of CMYK print - transfer of print from the first drum to the second should be taken into consideration. Therefore always have the lighter color in drum 1. ie Pass 1 M2 C1, Pass 2 K2 Y1.