I'm a little surprised that the Lite-on isn't reading them well, as Lite-on drives are generally pretty good at this. Their overall rep for burning DL media has never been that good, though I'm sure there have been exceptions.
If your old drive is in good working condition, and is actually an Optiarc 7201, you might not need anything else.
The Optiarc 7200A and 7200S are regarded as two of the best overall drives made. They compare favorably with darn near anything else. I don't remember much about the 7201 though.