Hi there Mceljo.
I am a newbie to AudioGon and came across this thread (mainly because I also have TA Ultra MM2 Interconnects, so was interested in your take on burn in time. I have them between my DAC and Pre and between Pre and Power Amp).
I have been running the cables since January this year and would totally agree that it takes time to run in properly.
The cables have now achieved in excess of 200 hrs and, in my system, sound wonderfully transparent and extended to the frequency extremes. I am very pleased with them (I perhaps should add that I upgraded from "old standard" Super TA cables and I must say that IMHO the Ultra mm2 surpasses the old Super in all respects).
I was also interested to note that you have now gone to the Reference - any good reason for the fairly quick change from Ultra to Reference - have you found significant improvements?
David