What is the weakest link in my C system

Looking for a sound advice on the tweaks in my "budget" system, which I'm pretty satisfied with, but the quest is always to make the sound a little better. CD player: Cal Audio DX-1, analog out via Straightwire LSI Encore to Adcom GFP 565 preamp; bypass out to Rotel RB-980BX via Straightwire LaserLink and normal out to NHT SA-2 via Radioshack gold; and then Kimber 4TC from the Rotel to NHT Super Zeros and BIG copper caples from SA-2 to NHT SW2. I am in the process of finding/making High Pass filter in the signal between Pre- and Power-amp to improve the headroom of the Super Zeros (any advise on that would be great!) So what cables do should I replace (never mind the Radio Shack, thats temporary) , and with what at reasonable prices? (I'm still in Graduate School). Any suggestions would be greatly appreciated.
Simple Watson; Pull the electrolytics from the Super Zeros crossover, replace with high quality metallized polyproplenes, replace wire internally with better quality Kimber or something. Imaging, detail and dynamics will improve dramatically for about $60. Done mine for a travel system and they even have (some) bottom end. Yeah, really! Good Luck.
With all the cables you're using, why not check out the more affordable Stealth cable listings (click on "Pricing") on www.InterlinkHouse.com/. I have a full complement of them in my system, and it's never sounded nearly so good.
the weakest link may very well be the 565. try and find a good used tube pre and youll be amazxed.. the arc 2p3a1 i got for low$ opened up the dynamics and air that i thought was limithed by my 555II. tkubes in the front,ss in the amp are a very fine way to go. my friend uses counterpoint sa2000/adcom 5800 driving ml requests to wonderful effect. the adcom amp naysayers are full of crap. they arent bright.