Monarchy DIP/Unsampler boxes effective tweak?

Very effective, dejitters and softens the digital edge. There are some reviews posted on the Monarchy Audio site, check them out.
In may experience the Upsampler sounds better, but it does not work with all dacs. The DIPs do, however.

I bought a DIP Classic primarily for its s/pdif to AES/EBU conversion, but found to my surprise that it significantly improved the sound in my setup (Theta Miles > DIP > z-Sytems RDQ-1 or Behringer DEQ2496 > Benchmark DAC1). Not a night-and-day difference, but worthwhile to me. No experience with the upsampler.

If you can get your hands on a used Camelot Dragon it is even more wonderful

Has anyone experimented with after market power cords on any of the DIP's? If so have you noticed an improvement versus the stock cord? Thanks again...

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.