You will have great fun stripping down a P bass and upgrading it , I’ve done it and it was a really good learning curve, I used google and YouTube mainly, I had upgraded a few jazzes but really enjoyed the P, my only suggestion would be to buy a fender, that way it makes it easier to source the parts. This is my one I’ve nearly finished, it’s a 22 year old body, my favourite old jazz neck, tonerider pickups , vintage bridge, and a kiogon loom , I love it . I’m sure @Cuzzie can offer some good advice, he’s more experienced than myself and he has done some nice builds 🙂