Jh2os,
The factory cord is all you'll ever need, as Krell or any other reputable amp manufacturer will confirm. Sure, some companies are beginning to market certain brand names with their products to increase sales, but once you understand what's involved with typical linear power supply requirements (transformers, rectification, filtering, and possible regulation), exotic materials will only gain you a FEW milivolts (if any) over a properly sized "stock" copper variation. Typical incoming AC voltage varies more than that at any given moment. Oh, and as stated in several other threads, don't forget about the non-audiophile outlet wiring behind your sheetrock walls. Nothing fancy there, right?
Don't take mine or other's word for it. Call several amp manufacturers that aren't marketing cords. If it made a difference, all of the combined engineering would agree, along with decades of electronic principals. Put the money into component upgrades.