That is a fair price for a LS25 mk2. I sold mine for $2400 a little over 2 years ago. Ask if the remote works. Audio Research no longer has replacement remotes for the LS25 mk2. It is a wonderful sounding unit. And one of the last of the truly nice classic looking ARC preamps without a display screen. The Ref 5se is suppose to sound best with the display screen turned off. So I never got the whole point of the display screen.
I use a cheap GUSTARD USB Converter to go from my computer to the DAC8. First keep in mind that the Ref CD7 has a better all tube DAC inside. The DAC8 is solid state. Also there are a lot of variables with computer audio. They are not built to play music. Computers are noisy (RF/EMI) and it takes work to get them to sound good. The Aurender is a one piece unit with a hard drive that is built to play music. You don't need a computer. If I got one with a DAC, I could get rid of the DAC8, USB converter and extra cables.
They are truly beautiful. I got a real super deal on my speakers. They were a dealer demo and less then a year old. I don't think they were completely broken in when I got them. I listened to them a few times and really loved them. They are not the type of speakers you bring home for the weekend on a whim. Then I read a review that said. Some speakers sound this way, other speakers sound that way. The Elipsa SE don't sound any way. They just sound like music. I totally agree, I can't see ever wanting to upgrade them.