When to choice XLR over RCA ICs.

If your IC connections are 1m or less is there a difference between using XLR over RCA Interconnects?

As one moves up the ICs cable lines with a manufacturer (ex. Audioquest) which connections would you upgrade first and in what order.

My system is McIntosh (C12000 two part preamp, Men220 room equalizer, MC611 mono-amps), Audioquest (AQ) Niagara 5000 line conditioner, and Hi-Fi Rose 150b streamer. 

I am currently using AQ Black Beauty XLR ICs. I have a pair of 1m Firebird RCA ICs and would like to replace one of the Black Beauty ICs in system configuration. Future upgrades looking for recommendations. 

Presently using a AQ 2m Thunder 20A power cord from wall socket to Niagara. 

Using 4ft AQ William Tell (Silver) bi-wire combo speaker cable (mono-amps to 800d3 speakers. 

Thank you, Please advise.

Bob