Thanks for the input and uploads, Rick.
Amplification and/or reproduction is such a multi-headed beast. Try as we might to find a great One-Size-Fits all solution, I've bagged out of that mindset in order to bring the appropriate tools for the appropriate job. Sometimes there can be an overlap, but sometimes the tools required are mutually exclusive. My sound and tonal concept/goal doesn't change, but the way I get it does.
As much as I'd like One Cab To Rule Them All (or "one anything..."), it's just not always possible-- for me, anyway. One issue that I haven't seen addressed is not so much how a particular piece of gear sounds, but how it "feels" when playing through it. Transparency, extension, clean, dirty... etc, don't really mean much if it doesn't "feel good" or "feel appropriate" when you're playing. So much of what I hear is directly correlated to how the instrument feels while being amplified.
On low volume gigs, I can totally get behind more of an open and airy sound, but as the volume increases, I want something that focuses the tone/sound to be more punchy and direct. I wish there were a control on my master volume that would have a corresponding HPF and LPF to cut the extremes of the frequency spectrum as the volume goes up.
To bring back the sports car analogy, I've got a rig that can "get around town," a rig that is for those "delicate and beautiful" situations (listening audiences), and I've the "mid-life crisis sports car" that is only useful when it's floored. There is some overlap between the three, but at the end of the day, each one has something that the others don't. What I like about this setup is that the feel of the instrument is really consistent, particularly on upright bass. I don't need to alter my approach to the bass differently for loud gigs vs. soft gigs. I don't have to dig in harder on the loud stuff to get the same results that I'd get on a softer gig. I just play the bass as I do and let the rig work as it's intended to.