Master Coupler or Shunyata Diamonback ?

I'm thinking of getting a pair of powercords to replace the stock powercords I'm using right now, that came with my Theta Data Basic II CDT and Theta Gen Va DAC.

Since I've got US-spec, 117V models (I'm running them through a customised PS Audio P-300 powerplant that does the voltage conversion from 230V to 117V) I cannot really borrow anything from a local shop, since the euro power cords have different endings. As a resoult, I'm forced to buy something without listening.

I was thinking about getting a Shunyata Diamonback or a Synergistic Research Master Coupler.

Any input would be apreciated. My budget is around 250$ for each PC.
Hello, the only one worth spending time with at all at your
price range is the Cardas Golden Ref. give it a listen.