Classe DR-6 vs DR-6R difference ?

What is the difference between the two Classe preamps;
DR-6 vs DR-6R ??

What I do know is the R stands for Reference and not remote. Also the DR-6R Reference version is harder to find preowned for sure, and has advantages over the DR-6 .

Thank you for all your help and clarification.

Bck when Armin worked for Classe and was the guy you spoke to on all matters when you called I asked the same question...the answer was that they were and are the same pre, no differences.
I think the R did if fact mean remote and not reference. I did consider buying one when they were still in production but a casual AB with other preamps costing far less made the choice of the ARC LS3 very easy. imho.
I own a Classe DR-6R and DR-6 and there is many difference.

Several additional upgrades are on the Classe DR6R verse the DR6. Balance input and balance output. More inputs, also standby mute, reverse phase, mono, more selections on the phono impedence selection and etc. True balance circuitry was designed in the Classe DR-6R. The Classe DR6 did not have true balance circuitry. Better attenuator, went to a heavier steel casing, so the DR-6R is built better than the stock DR-6. Also the Classe DR-6R had an improved power supply cord over the DR6. There were a few other improvements also. Classe wanted to be a world beater verse Threshold, Levinson, Krell and Rowland at the time.

The Classe DR-6 msrp was $3295. The Classe DR-6R msrp was $4995.

The Classe DR-6R was a very limited production piece because short lived. The Classe DR-6 Mk 2 was released soon after and cheapened a bit to meet the msrp price of $3495. Classe at the time/ Dave Reich wanted to stay under $3500 msrp because of the wide competition of other state of the art preamps.

Sonically the Classe DR6R is superior over the DR6.

When Classe released the DR-6 mk2 they reverted back to the design of the original DR-6 to keep costs down. Classe then released the DR-6L line level without phono at $2995 to compete with Threshold and Krell's line level preamp.

"The R does stand for Reference". Classe DR6R never had a remote.

So there is quite difference between the two Classe preamps.