Viggen, I do like these acronym, sounds like a Saab model. I do not trust those autotransformer anything in my path. I have read much of the work that goes into them, and people seem to like them, but if you see the reviews, the praised that come from using them, most of them come from owners of Atmasphere OTL or some other OTL design amps running what it seems to me more of a heavy loaded speakers. The drivers you have are nowhere near as difficult or outrageous as those that I have seen partnered in those reviews. I recall many of them being some sort of electrostats and some even using the Merlin VSM. There is no way I can see how the autotransformer will benefit CONSIDERABLY the set up you already own. I am striving for simplicity, closeness to the source and putting a autotransformer, I do not know if THAT is going to be too good. I know the designer of the AUTOTRANS said that the signal does not go looping around the winding cords, but WHY add more distance, one more something while you try to be immediate in the sound, with the mm between signal and amplification as with the CARD? I vote to dump the idea of adding the AUTOTRANSF.....it will change the sound, but I doubt it will be an improvement that might justify the cost of the time to get it and set it up.
PS: Cannot afford to pay moving people for the gear I have, cannot trust them with such sensitive equipment, so being a Do myself type, I am trying to DIET my extra audio pounds.