MB Quarts are, in my opinion, some of the best speakers you can buy. They can get pricey but they sound amazing. Also Focal, Diamond, and Infinity get my vote. I have not heard the Pioneer Rev series yet but I have heard some people raving about them.
There are quite a few very good head units out there, and if you intend to push your speakers with a head unit's built-in amp, I would recommend going with one of the alpine v-drive models, or a pioneer/premier with the mosfet50 amp chip. The alpine one in particular will go pretty darn loud before distorting, but if you're trying to have an SQ type system you might want to consider using an external 4-channel amplifier anyways.
Technically the motorized faceplate models are more likely to give you problems down the road, but in general if you take good care of the head unit and use common sense (i.e. don't try to force it closed or open/close it repeatedly) you shouldn't have a problem. Also, most of the head units that you'll be considering are probably going to be the motorized faceplate type, so you might not have a choice in the matter.
My personal favorite for head units has always been Pioneer. The last few years they have come out with some really solid head units with a lot of innovative features, and they really do last a long time. In terms of the little nit-picky things like ease of use and button action/movement they have always been right up there with the best of them. These may sound stupid and insignificant, but after daily use they become pretty important.
I was going to suggest the Premier DEX-P9 (with the DEQ-P9) but you said $2,000 for a head unit is absurd....but hey we can all dream, right? Depending on where you bought them, the two together would probably run you around $1800 total. When used together, they will provide amazing sound quality and give you COMPLETE control over equalization functions/settings. It's fun stuff, let me tell ya.......
Also of note is the Eclipse CD8053...haven't heard this one yet but the specs certainly scream "SQ." 16 volts for a preout is kind of silly, but the preamp DSP feature looks pretty cool.
I think that as long as all of the equipment is 100% properly installed (wires routed properly, components grounded properly, shielded RCAs used, optimal subwoofer enclosure sizes used, etc.), most of the difference in sound will depend on the speakers and on what type of subwoofer enclosure you use. I'd be more concerned with those two things than with specific head unit models, because as long as you stick to the main high-end brands and models, ground the unit properly, and use an external 4-channel amplifier, they will in most situations all sound pretty much the same.
From there it's just a matter of choosing one that has the features that you want and that will fit your budget.
Ethan
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"Patience, persistence, and perspiration make an unbeatable combination for success"
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