Monarchy DIP/Unsampler boxes effective tweak?

If the DAC does not reclock the data then the DIP can be very effective. Inserting the DIP between my Marantz CD67SE and Monarchy 22A DAC made more improvement to the sound than adding the DAC to the CD player had made.

If the DAC reclocks the data or if the transport has very low jitter then the improvement will probably be less marked.

I can't say whether a DIP would be better than an upsampler, but I'd probably choose a simple DIP as it will be less expensive and will give you an idea of how much your system benefits from reduced jitter.

No, but I have put a ferrite ring on the existing power cord, just in case the DIP is a source of noise on the power supply to my other components.
I'm not sure that I noticed a jump in performance, but I tend to assume that digital components have the possibility of injecting some level of noise back into the power supply so a ferrite on the cord seems like a wise precaution.