Well finally an answer!
The old version had a setting whereby you could overwrite the default speed CDBurnerXP sets it to after it automatically detects it. That option is gone as far as I can tell.
I know the media I buy is capable of burning at 2X or 4X if I want it to. Rule of thumb is that the slower the burn speed, the fewer coasters I produce and I get a longer lasting burn which means a longer lasting CD-R. That's been my experience since the good old Nero 6 days.