How important is powercord synergy?

If you can hear the difference, then it's important. I've tried about 20 or so PC's and some made a big difference, some didn't. System matching/synergy has to go hand in hand with what you want to hear.

Also, a cheap power strip/surge protector may do more harm than good. I'd suggest plugging directly into the wall to determine if there's any difference. Additionally, if you don't have dedicated lines and/or upgraded outlets, you might want to look into these.

Lastly, when you buy a PC, you may be surprised to find some of the lesser priced cords do a very good job, especially in the DIY area. I have two in my system & am very happy with them.

Powercord is important depending on length and current it needs to drow from the wall socket. If you intend to use a long powercord you should take a thicker gauge

If you take care of what's inside the wall and wall sockets you may find little-to no differences with properly selected powercords.

A power conditioner is great if you have enough voltage i.e. 120..122V and assume a loss of voltage in conditioner by a couple of volts.
Amps are OK if input voltage is a-bit higher but "hate" lack of voltage and bring an unpleasant distortions.
So I'd rather think of PC later than sooner before certain things are taken care prior and maybe you won't need it after all.

Dedicated lines will make bigger difference than any power cord upgrade. Improper power cord can damage your amp, this is why you will always get a cord that can pass enough current for your amp to last. Don't use cheap power strip, this could damage, or at least degrade your amp. If you can hear any difference a power cord change might make then go for it, It would be last on my list of upgrades but as always in audio, keep an open wallet. (I mean mind).

To wait to address any AC deficiencies (which we all have) is bass ackwards IMO. But then again, I don't use any power cables per se.

I would think theoretically, that if one properly addresses all electrical AC before purchasing any components would be the best way to go.

Any system capable of a certain caliber of sonic quality or better will benefit from an AC environment that has been properly addressed.

For example, assume one installs the following first:

o Dedicated circuits and lines from the service panel for each component with appropriate amperage.

o Aftermarket or custom 10 ga. 99.95% OFC house wiring for all lines.

o Quality-oriented audio-grade outlets for all dedicated lines.

o Quality-oriented line conditioners for each dedicated line. (Yes I am aware there are many inferior line conditioners).

Once the above is done, then no matter which components one purchase thereafter, one should hear close to or the very best each component is capable of producing.

Thus allowing one to make better informed decisions.

Caveat:
This methodology would not necessarily work best for those components whose mfg'ers have already attempted to suppress AC noise by altering/filtering certain offending frequencies instead of properly addressing the AC noise itself. For these components, a line conditioner may not benefit.

-IMO

Stehno, very interesting theory that makes sense to me. Everyone seems to be saying "get all components first, then match cables." I understand this for IC's and speaker cable, but I question this for PC's. Problem is, I'll have to wait approximately six months before I get the new quicksilver mono's. I plan on upgrading the PC and putting in dedicated lines anyway. Why not do this before the final component purchase since I'm gonna do it anyway. That way I can enjoy the upgraded power supply sooner. Has anyone had synergy problems with PC's? Is matching PC's with components as critical as IC's and Speaker cable?