my wife and I drive matching bavarian chariots, at least for the most part. Both are 435i's, yet her's is a grancoupe and mine is a coupe. She has the hot red leather interior. It's used mostly to transport lots of packages to the post office ----- and to your recent post, the Spring Dac module is only half used when in SE mode or RCA output. and the entire dac module is used for balanced mode or XLR. XLR has better common mode noise rejection of course, but to most people it will be hard to tell much difference between the two outputs. 5V for XLR and 2.5V for RCA outputs... So if you can match volume of both inputs its likely it will be hard to tell the difference in most situations. Some may claim differences though. Using interconnects that are the same for RCA and same for XLR would be needed to compare between them fairly. and a preamp or integrated amp that also is well built to accept either SE or Balanced. I would be curious to hear from anyone who has tried them and had any significant differences. Exactly! in most cases if the setup doesn't have an environment of excessive noise, it will be hard to tell the difference. XLR balanced will just ensure the very best sound quality, so most will prefer to use this output. Personally I use both outputs... one goes to a headamp and another to a preamp. Our other two Spring dacs are setup in a similar way too. Both outputs actually work simultaneously and seems to be another common question I get a lot! odd, but I never use them at the same time, but its nice to have outputs to multiple pieces of gear. Most people may want to have a loudspeaker system and headamp system hooked up to their dac.