Well... In my opinion. Powertrons will have better note seperation, but be really similar to what you have as far as gain and output/response.
DeArmonds require a lot of measuring and steady precise work but are do-able.
The classics or filter-trons will be more "gretschy" of course. Classic+ might be a better option if you want the gain and output/response with a more gretsch sound.
If you like P-90 tone, TV also has them in a Filter-tron/Classic style mount,
Also has a Magnatron which is bassier... (trying to be a Dearmond style but realistically they're rumored to be more like stacked strat pups) both of these would be cool in the neck with a Classic/Classic+ in the bridge.
Also a Super-tron in the neck Classic+ bridge would be pretty sweet too.
If you dont wanna think about any odd "em2 conversion" and Humbucker ring kits and stuff, GFS makes some neat options IN HUMBUCKER mounts. so you just need to adapt your rings with the "mid" mounting hole instead of the "north south" adjuster from the "guild" mounts that come on the newer 5120/22's.
The retro-tron line has Different P-90 bucker mounts, and also humbucking p90s called dream 180's, they have the memphis's and the nashvilles, which are kinda gretschy and ric flavored depending how you hear things. all in kinda different outputs. something for everyone I suppose.
I wouldn't worry about the Pots till they go bad, but your going to take them out anyways when you replace the Pup's. (You had better... I will curse you if you just cut and splice and it wont matter one bit... but you ought too
) I suppose it would benefit you to have higher quality pots as you wont have to replace them for a much longer period of time, and wont have to screw around w/ the harness till something goes wrong. The physical wires wont matter too much. Most of the guys who work on their own gear here will say the stock wiring is up to snuff. I agree.