Hello! I'm planning on customising my old Squier Affinity P Bass. I was just wondering, what pups would give it a nice warm tone? Also, would it be possible to carve out a hole and insert a jazz pick up? I have no knowledge on wiring, so i would seek help when doing this.

my customisation plan is to repaint it white, replacing the current cream, replacing the pups, possibly adding a jazz pup, installing a new bridge and scratchplate, and possibly replacing the tuning pegs and machine heads.
Plenty of basses have a P/J pickup combination, so it's more than doable. In terms of the bridge, I'd pop in a Gotih of some description- cheaper than the Leo Quan Badass bridges, but still very, very good.

In terms of pickups and electronics- would you be willing to go active? If so, Aguilar and John East do great preamps, and Nordstrand do some wonderful vintage style pups. If you'd rather not go active, Stellartone do a really versatile tone pot replacement called the Tonestyler Bass. It has a number of selectable treble roll-off points.

And I think a pickguard made from bubinga or rosewood against cream would look quite cool
Gotoh bridges do look tasty!

I am tempted to go active, i really like the tone from active pups

ahh that is good to hear, i'll look into carving out a hole for it, my missus's dad has a custom built bass and it has a jazz pup cover which looks gorgeous ^-^

thankyou for the tips!!