What interconnects work best with Audio Research?

Agree, CARDAS is the brand for you. Be extra carful about used Cardas.. they have had a problem with fakes! Make certain you buy from a retail seller, or (used) from folks who have a long and solid reputation who are 'original owners' and can proove it.
(Few other cables have the 'look perfect'forgery problem Cardas has)

Thanks, which of the Cardas line up should I use.......

Also consider Harmonic Technology Magic IC and Pro-9 speaker cable.
These no-nonsense cables sound wonderful and are resonably priced on the used market.
I've used HT with ARC, BAT, Parasound etc. and have never been disappointed or felt like "something was missing".

I used Audio Magic cables accross the board with my reference Audio Research set-up and it worked great. The Audio Magic line-up is similar to the 'silver litz' cables that Audio Research use to sell except that they are updated and more refined.

Over the years, I have seen ARC products using AudioQuest wire frequently in shows and demonstrations, especially with Vandersteen speakers. The largest ARC dealer in the world for several years carried AQ almost exclusively and sold me on them. They are hard to describe other than transparent or neutral. If that is what you are after, give them a try.