Speaker Cables for Martin Logan SL3

Need recommendations for speaker cables for my Martin Logan SL3. Looking to spend between $500 - $1000 for a pair 10' bi-wire cables. Would consider either used or new cables. Looking for cables to smooth out system and improve imaging. Other components: EAD Powermaster 2000, Integra Research Pre/Pro RCV-7 and Theta Miles CD Player.

I recently switched to Transparent bi-wires for my Martin Logan Quest Z's. They sound terrific, and very reasonably priced (I picked them up new, at a discounted price, from a local dealer for $300). Associated gear: BAT VK30 preamp, BAT VK500 amp, Oracle Delphi IV/SME345/Grado Reference, YBA Integre CDP, Magnum Dynalab tuner, Lehmann Black Cube phono stage, Grado headphone amp. Power cords are Synergistic Research Reference on everything except the amp, where I'm using Harmonic Tech. IC's are Goertz Mircopurl copper balanced (preamp to amp), and Transparent MusicLink 100 on source components.
I also use Transparent with my Martin Logans and it works great. If you can swing it I would recomend at least the "super" line which is about 1400 new, 700 or so used.