McIntosh c2700 users please chime in?

1. Is there a big difference (besides the upgradable DAC module)?

2. How much discount (5, 10, 15%) should one expect to get if asked?

I may be looking to sell my BHK pre and then pay the difference for the C2700. Nothing wrong with the BHK. I also like the idea of tone controls. Plus, its hard not to like the blue meters :)
I run an MC302 with a C2500 = Heaven.
I would probably be fine with the c2600 if the DAC was upgradable. The non tubed version (c53) is also on my radar. 
I just ordered  a new Macintosh C2700 tube preamp 1 week ago. I demoed the stereo store’s model for a week with my audio system in my home and made my decision to end the preamp search.

Next on the list is to pick a McIntosh amp to go with it.
Did you get a discount?
I bought a C-47 2 years ago, paid like 4k canadian which is a bargain considering the sound quality and the fact it has a dac built in. The dac quality surprised me, no need for more.