New Perpetual P1/P3 configuration

I have been busy modding a P-3A for a customer, who also asked me to design a new I2S cable. Since this is a proto, I am doing this for free for him.

Anyway, here is what I discovered:

After the P3 mods, the P1/P3 in typical configurations sounds a bit better, but the P3 still sounds better alone, and with the mods, MUCH better, with one exception. If I connect the I2S cable ONLY to the P1, the P3 imaging gets even better with horns becoming more coherent and solid. The cable I made improves this even more with better HF extension. I am not sure what the P1 is doing for the P3 in this configuration (which I call #5), but I really like it. I will be doing some scope probing this afternoon to try to determine what is happening.
And what mods are they?
KR4 - the mods include 11 traces that are cut, 12 components that are deleted and 18 components that are added, plus some point-to-point wiring. Non-trivial, I assure you. Takes at least 8 hours to do it with the right parts, equipment and a very strong magnifying glass.

As for the I2S cable effect, I was able to reproduce the effect with a mod inside the P3, making the P1 superfluous, IMO.
I did play on the mod, replace the existing OpAmp to OpAmp627 and 2 more (cant remember model). Sound improves a lot after that.