What do $2500 speaker cables sound like?

They sound like disappearing Green Paper.

Just buy them  why spin the tires.  Make sure you get matching interconnects for the full blowen result .   Also don't worry about that speaker you use  

They sound like $500 speaker cables. And they sound like $15,000 speaker cables, and sometimes they sound like $20 worth of zip cord from Home Depot. Above a few hundred dollars for say a 3 meter pair (longer runs are going to cost more) and it's just whatever differences you hear. Either way, no way to know without living with them for a good long while in your system.

Its not the speakers , But the amp and cables you are running

MIT fan here having done really well on “new old stock” that can be found and not break the bank.  Have been really happy with the results, esp. afire “learning” about proper cable management which is crucial. (Shout out to MC for that one!)