DiMarzio pickups are my go to replacement split coil pickup when the stock pickups don't cut it. I bought this set to replace a failing set on a Precision Bass copy.
Everything you need is included in the packaging (a nice plastic box) - screws, wiring instructions and you can even use the foam as a mount.
What's great about these pickups (aside from their already great sound) is that because they are four wire, you can fit a 'Dual Sound' switch, which allows you to run the pickups in Parallel (normal operation) or Series, which gives a bit more output. I like to refer to it as the 'loud switch'!
The pickups look great - I've often felt that the cream goes with any colour bass, particularly black with a black pickguard.
The pickups have two ceramic magnets sandwiching the pole pieces, which can be adjusted to balance string volume if needed and they have a great middy sound, which suits a Precision Bass perfectly - these were a popular upgrade in the late 70s and early 80s and they have that sound in abudance.
With the tone control wide open, you can get a fairly aggressive tone out of them, but by rolling off the tone even a little, more vintage tones can be achieved.
A bargain for the price and a worthwhile upgrade to your P-Bass! Highly recommended.