The suggestion of bypassing the Blast city AMP, using another amp and another PSU to power that amp is what I'm referring to. I'm not criticising the idea, it's just seems a whole lot of work for not much benefit.
The sound on the Blast City is pretty good imo, especially when the speakers haven't degraded. Using a Naomi amp to power Blast City speakers is asking for trouble imo, you run the real risk of damaging them.
I'm not against upgrading sound in a cab as I've upgraded the speakers on my Astro City cabs and also upgraded the speakers on my Sega Rally 2 cab to those from a Model 2 Sega Rally 1 cab. I also swapped out one of the Amps in Sega Rally 2 for one that has EQ jumpers, not sure what cab it originally came from but it sounds much better!
Anyway, good luck with your projects as I enjoy reading your updates.