Drop down to the CONCLUSION if you dont wanna read all the details.
I recently grabbed the Friedman SS (I fondly refer to as the SS Supreme) that Jeremy did similar mods to.
I've owned the most of amps that Friedman has put out. I enjoyed all but 1 of them (wasn't a fan of an early, noisy, original PT). They have better gain than anything Marshall is putting out, with a fantastic effects loop and master volume.
The Phil X was my favorite, due to the great sounding single channel and more open sound, compared to the others. Plexi to hotrodded JMP, it was good.
The original SS was my 2nd fav.
Jeremy's mods made the SS V1 more versatile, opened it up, making it less stuffy in the mids, brighter, tighter, with more gain options, including the most useful NFB and Depth knobs. He basically fixed the "polished/refined" sound of the Friedman amps, that many people wish was more "Marshally."
CONCLUSION:
I'd be tempted by the GZ modded X if I hadn't scored the GZ SS. Knowing what I know now, after having the SS, I'd buy it in a heartbeat.
I highly recommend the GZ modded X to anyone wanting a versatile, Marshally sounding amp that goes from vintage crunch, to brown sound, to heavier 90s sounds, to tighter and ganier modern sounds. I bet Phil X would pick it up himself, if he got to play it.