What Raquel wrote is interesting.
I've used SR Sig 10 active x2 biwires, 21ft long for sometime now. Used with several amps, and several speakers thru that time period. All with very good results.
I too am considering for some future event, shorter cables in the rearrangment of my stereo. i think then too, I'd be inclined to enlist something akin to cables I'm using upstream. At least in the same house, if not the same model.
Going that way seems to indicate you'll have a better feel for the outcome if no preview is allowed or sought prior to purchase of them. Depending on which presentation of the sound I'd be willing to spring for, in my case it'd be either Nirvana SX latd's... or HT Magic II sorts feeding my speakers.... as nothing now in the current SR line equates to the Sig 10 identically... I find the Sig 10 very very neutral.
The SX LTD. has a more refined and smoother presentation than does the Magic II ICs. albeit each conveys lots of detials and ambient cues. the Magic IIs are a bit more vibrantly colorful while remaining refined and an easy listen. So one is easing off the sheerest edge of each leading notes edge, while the magic IIs dont seem quite so predisposed. The Magic IIs also would come in less costly.
I feel it's more the involved process to seek out some mixture of unlike, yet friendly cables for one's system, than it is to go 'whole house'. The one road beckons extreme performance while implying as much intrigue in the doing of the assembly. The second path says, simpler and safer with perhaps as good results... perhaps.
I'd suggest if you're inclined to drop a pretty penny here, to rent some thru the cable co. first. This ought to gain you way more appropriate solutions.
VEry good luck.