Hi DaveyF, glad to share my insight.
I don't think what I'm about to say will be revolutionary to anyone on this forum but we'll see
Considering what component upgrade may have the greatest impact on any particular system is what we all struggle with; either in our personal system, a friend's system, a potential customer or even a system we're preparing to present at a show. It's an exercise we do regularly. And Leif and I consider these things together; we argue, we experiment, we confirm
First, let me lay some disclaimers down.
1 - I won't speak for any hypothetical product or generalize the performance of all the products in a category. Instead I'll try be very specific.
2 - I don't consider the isolation of electronics a "tweak." From my experience and in my mind it's a critical
component to achieving higher levels of performance; especially so in very high-performance systems.
3 - In every situation, your miles will vary.
Considering Leif's current home system, he has our $40K Endeavor E-5 MkII being driven by roughly $8K in Audio Alchemy source and amplification. And he presently has a modest rack that I would estimate provides very little if any isolation. From my first-hand experience of adding $6K of the original CS footers (zero CS2 footers), the improvement in the signal being transmitted by the Audio Alchemy front-end to the E-5 MkII was far superior (by a magnitude not a percentage) than swapping out the line stage and amplifier with ones that I highly respect (and have won several Best of Show with) that cost 7.5 times as much. Clearly the footers were the better choice to me, the greatest ROI. In this case, the weakest link in the chain was isolation, not the quality of the front-end.
Now on to the hypothetical proposition of swapping out the E-5 MkII (again $40K) with the ULTRA 11 ($300K or 7.5 times as much), I would
estimate the improvement would not be as great.
While the ULTRA 11 is far more revealing than the E-5 MkII, the weakest link in Leif's system was the isolation issues with the front-end. So upgrading the loudspeakers would have little positive affect.
In my consideration, it might even degrade the overall performance with the ULTRA 11 exposing issues that are less perceptible on the E-5 MkII. I think the old hack "garbage in, garbage out" would apply in this case. Loudspeakers perform at the level of what's put in front of them, period. They are incapable of improving the source, only diminishing it.
So in this case I think improving the signal going into the E-5MkII is the better choice than breaking our backs moving the ULTRA 11 into Leif's sound room. You haven't seen his stairs. Let's wait until we significantly upgrade the front-end first