Beautiful system! I really think that you would love the McIntosh....But I would give another one a look... the Manley Labs Jumbo Shrimp is great for injecting a lot of rich organic earthy quality with a real palpable sense and a huge soundstage with plenty of rise and decay, I say this because you currently have a Chinook and the combo is amazing! Its what I use over a Mac pre amp. My brother has the C2500 with the exact same system as mine, and it sounds very accurate warm and detailed as hell. I have a Project Xtension 10 and I spin a lot of vinyl, and I wanted something special sounding. You would not be making a bad choice either way. IMO.
Matt M P.S. never heard the SF pre amps
Matt M P.S. never heard the SF pre amps