Mcintosh or Pass to JBL 4367

Take a hard pass on Pass preamps. I have had both the XP20 and 30 and found the sound sterile and fairly lifeless. Consider a Coda solid state amp and a great tube preamp such as the Aric Audio Motherlode.

@n_brio

Cary Audio SLP-98, low noise dual chassis class A triode preamp with nice high dynamic gain and wonderful 6SN7 tubes feeding a Class A Pass Labs XA25. Bingo synergy preamp / amp / speakers. The JBLs do not need so much power.

If you want to take it up a few notches the Cary SLP-05 and Mac MC312 (my system) sounds fabulous. 

I’m using a XP 10 with a Pass 250.8 on Maggie 3.7i and the sound is magnificent on all types of music. Somewhat tube like with great bass and high end I can listen for hours. You won’t be sorry with the 250.8.

no experience with Mac products 

@n_brio 

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.