I'd probably swap the mount for an equatorial mount (Sky-Watcher EQ6 or similar), and use an off-axis guider, with a modern CMOS like the ZWO-ASI or one of the QHYs as imaging camera (much cheaper than the CCDs, and just as good if not better). At prime focus (i.e. without a focal reducer or Hyperstar-like system) getting pinpoint guiding with a secondary guidescope is tricky, but an OAG does wonders...starlight express makes the best in my opinion. Optically the C8 is still fine, you might want to re-collimate it, but that's a bit of an after thought. Calculating the backfocus for your optical train might be tricky. But once you have it set-up on a computerized mount (getting plate solving to work would probably also help, I can recommend Sequence Generator Pro) then you're good to go!