In my experience (and I've been testing Stealth cables for Interlink House, Inc.), preamp to power amp is the most important link: I could hear differences most clearly there. If you got a pair of interconnects from a source who allows you to return them (www.interlinkhouse.com, maybe The Cable Company, maybe a dealer), you could try this for yourself. Put in only one of the new cables, in each position, and see where you notice the biggest improvement. I'll bet on the preamp to amp position as being the most revealing. Stealth comes with a 30-day money-back guarantee, besides being a lot better than anything close to their prices, IMHO.
upgrading interconnects
i am going to upgrade my interconnects one at a time. which one first? between cd and preamp or preamp and amp. they will be the same cable when complete. thinking about the kimber hero. have a citation 24 amp,citation 21 preamp and a hk hd-710 cd player, paradigm studio 60 speakers bi-wired with kimber 4vs speaker wire.