"I just listen to CD & Internet radio streaming, do I need c2300 at all?"
Uhhh...I don't know, but I'm feeling your pain!
I also have a 275 + 804S, so very similar setups, and also listen to digital only. So, do we need a preamp or a DAC with a good volume control? I dunno!!!
Lately I've been drifting towards using a good albeit simple preamp. I love tubes. Now the C220 and C2300 are too expensive for what I feel you get, especially these aren't balanced designs and have too many bells and whistles that I don't need...I guess you pay for the McIntosh nameplate.
My current short list includes a couple hot rods like Lamm LL2 and First Sound Presence, and others like Joule-Electra LA-100 or LA-150, and Aesthetix Calypso. I have not auditioned these though.
Thought I'd share my confusion and maybe add you to the list!! ;-)