Which is better longer xlr or speaker cable

I have just purchased my first mono amps (Nuforce Reference 9V2SE's) giving me some new cable options. Currently I run a one meter pair of XLR and then four 5 meter pairs, as I biwire, of speaker cable. With the mono's now I can also do a 5 meter xlr and short speaker cables.

Which should produce better sound. And for equal sound quality, which should be less expensive. Any recommendations for a reasonable cost way to do this? I would like to get in new or used for under $500 for whatever additional stuff I have to buy. In option one I will need new speaker cable, in option two, new IC xlr. Is it OK to have different lengths of cable, probably 3 meters to the closer speaker?
Thanks