Best XLR IC's for around $300/pair?

Audience, Acoustic Zen at that price point.

At that price point; Kimber Heroes would be my first choice. There are reviews galore, online. This site offers the option of finding the price, based on length and connectors: (http://www.needledoctor.com/Kimber-Kable-Hero-Audio-Interconnect-Cable_2)

Signal Cable,...other manufactures should have Signal cable wires for their reference to chellenge their best and at the same time be ashamed of the market up and marketing surrounding many of these ultra expensive wire.,...Member Syntax is right about Signal Cable being The Most underrated cable manufacture in the business.

try either of these from Take Five Audio,

Neotech NEI-3001 Balanced, Furutech 602/601 XLRs, Cryo Treated

or

Mogami 2534 XX Series, Cryo Treated, Neutrik XX Series XLR

I have both but with RCA ends, the Neotech is a bit full with solid bass and beautiful midrange tone and the Mogami is a bit more neutral and possibly more detailed.

The Neotech would be around $300 for 3 ft and the Moagami is an absolute steal at less then $100 for 3 ft.

Cabledyne. Copper version is in your price range or the silver for $100 more. I have not heard a better cable in my system. Very open and neutral and superior build quality.