What would you upgrade next?

I'm with Bob--the preamp is likely a big, if not the biggest, weak link in your system. The good news is you can buy a high-end stereo preamp and just plug the front L/R outs from the B&K into any line-level input on the stereo preamp(the Pioneer also goes into the stereo preamp, which is obviously connected to the McCormack). This way for critical 2-channel listening you're only using the stereo preamp, but you can still use the B&K for movies/surround music--best of both worlds.

Also high on my list, although well behind the preamp, would be to mod the Pioneer(talk to someone like Ric Schultz at EVS, Stan Warren, Dan Wright, etc.) that will clean things up quite a bit, and also sending the McCormack to Smcaudio for the Rev. A mod.

If you're happy with your speakers I think these three upgrades would make major improvements, although again I'd definately start with the preamp. For what it's worth and best of luck.

Tim

Damn--forgot with the Pioneer you're likely running a 6-channel output. The McCormack preamp will likely work, but whether it'll be a significant improvement would be the big question. I had the McCormack RLD-1 stereo preamp in my system for a while and it's a good preamp but I thought a tiny bit veiled relative to some other high-end preamps I've had in my system. I'd say give it a try, and if it yields a good improvement and allows you to do the 6-channel thing it might be a good move. Definitely find a dealer who will let you demo it in your system at home before you commit.

If 2-channel is still your priority(over multichannel music) it still may be worthwhile to check out some other stereo preamps to see what they can do for your system. It might be a good idea to do that anyway just so you have that as a reference point for comparison. I don't know how much you want to spend, but I like preamps from Pass Labs and Ayre. Marsh makes an excellent preamp at around $1000(P2000) if you can find one to demo, and Placette(passive, but should work well with McCormack, but Pioneer would need to put out 2 volts for this to work) makes some kick ass preamps that you can demo for 30 days risk free. Just some options if you didn't already have some in mind. Hope this helped.

Tim