SCD-1 mods and outboard DAC -Help


Allright, probably a silly question, but:
Am I right in believing that mods to the cdp would be pretty much useless if an outboard DAC (thinking of Benchmark) was to be used? The mods I'm refering to would be upgraded clock, and board resistors. Would power supply mods make any difference?
Perhars a better question would be, what mods would be completely useless when using an outboard DAC, and what mods would still be effective?
Either way, I want to keep the SCD-1, as a transport it is a great foundation. I'm having difficulty deciding on a new DAC, mods, (Reference Audio Mods) or a combination.
Thanks, Frank.
fotis_k