PS Audio XStream biwire, what are they worth?

Last night I heard a Nordost $6K Valhalla 2 power cord improve a ARC-Maggie 3.7 system by an order of magnitude.
If I had 6k to spare I'd buy a pair, but sad to say, I don't.

Schubert, no worries, you can get it next year used for $600 if you have'em spare(I don't even have that much for it and stuck with stock:)).

Czar,

I recently replaced a stock cord to my mhdt DAC with a Pangea AC14SE and it improved the sound noticeably exactly as advertised I would assume for the reasons advertised having to do with noise control. Cost was very reasonable, < $100. Nice product! Good Value. Build quality speaks for itself.

Then on an audiophile high I replaced the stock cord on my ARC sp16 pre-amp happily as well.

My opinion is a cord that can help keep EM and RFI noise to aminimum is a good add especially for digital gear like DACs. Worthwhile perhaps as well for low level analog devices like pre-amps.

Have not tried for power amps to date. Pangea AC 9 is for that. ITs more about current delivery with power amps wheras with noise mgmt with line level gear, but my system has all the muscle and drive I could ever want already, so no rush there.

Mapman, I'm sceptic if my pro-grade DAC/preamp Mytek will benefit from aftermarket PC as well as class T Sunfire 300 amplifier.
PC designed by Bob Carver for it with no neutral recepticle less-likely can be replaced by aftermarket PC.
Furman power box I use provides both: noise filtering and protection...

I've used a similar power strip for years. The cords still seemed to help. I could hear a similar difference with both the mhdt tube DAC in my av system upstairs and with teh mndt SS DAC in my main rig downstairs. Power cords themselves can be a cause of RF noise. A product designed to address this effectively like teh Pangeas seems to be the key. So I think there is a good chance your setup might benefit. Of course a big factor is how good the existing power cords may or may not be in this regard, and how signficant the RF noise issue, which will vary case by case. I know with my main rig in general that I am constantly battling RD and EM noise issues both from my gear and other large eletronic household devices not far away, so I am always looking to do whatever I can as an insurance policy, and each time has paid dividends to-date.

With the Pangea's, the build quality is excellent and the price reasonable, especially at the recent going prices, so even if no audible difference, you still feel like you are using a good product for the task and not cheated.