I usually agree with the snake oil warnings, too - unless there is a real logical/scientific reason that a product should make a difference. There is an excellent, priced-within-reach power cord that might actually add performance - the Granite Audio 560. It has Double Toroid EMI & RFI Filters (one at each end), is hand built in the U.S., and is shipped already 80% burned-in (so no lame excuses for it's out of the box performance.)
Granite gives you a 30 day no questions asked in-home trial. If there's no audible improvement, you can return it (less shipping and credit card fees, if any).
Here's a reasonably objective review:
http://www.stereotimes.com/cables020402.shtm
or the Granite Audio description:
http://www.graniteaudio.com/cable/page5.html
I'm not affiliated in any way. I have bought one of their Preamps and and one of their power cords here on Audiogon (by posting a Wanted ad and being patient) and think they make great products.