I can't recommand enough the MAstery bridge!
I've installed one on my MIJ Jazzmaster, and it's incredible!
First of all it solved a lot of known issues, like string jumping out the saddles, general intonation and tuning stability.
Second the guitar got alive: unplugged it sounds a lot more resonant and loud! Plugged I had the impression the sound was thicker than before with much more sustain.
Huge improvement indeed!
For the pickups check out Creamery in England.
https://www.creamery-pickups.co.uk/They have a lot of Jaguar (as well as Jazzmaster) pickups, and you can directly contact Jamie, if you have any special wishes (I still have to place the order, but we were talking about a customized a set for my JM, a Alt-88 Mid range with Alnico 4 magnets, and a slightly overwound '58 also with Alnico 4).