I have a pair of JBL 4349's which have a 12" woofer with a waveguide, similar to the 4367 (though the 4367 is higher up on the JBL food chain). I'm using a McIntosh C53 preamp into a MC312 (MC452 runs my JBL subs with an MEN220 as a digital crossover). It's delightfully smooth, never harsh, lots of detail and I can listen for hours with no fatigue. I don't feel the need to upgrade or make a change.
In my opinion, there is something to be said for synergy when choosing a preamp and amp combo. Your choices seem quite logical to me by choosing a preamp and amp from the same manufacturer. I bet both combos would sound fantastic.