NOOB Pickup question

[FuzzBoxVoodoo]

Hey All.
Well I have finally have my Bass Rig and Gear all fiqured out (for now:eyebrow and I want to fiqure out what pickups I might want to try to improve my sound even more.
First question is Im looking at getting one of those clear headless basses just for a fun stage prop but Im not sure that I could live with the sound,I think that the pickups are call p and J what does this mean? I have been reading different posts and dont get it I do know the difference between single and double coil (humbuckers) and active and passive pickups and EQ's but I dont get the p J thing.
I have a Eden Navigator/Carvin 1500 and a Genz Benz Shuttle 6.0 for my power side and Avatar 2x10,2x12 and Aguilar 2x12 for speakers and I just bought a MXR MX-80 and a Tech 21 SansAmp Bass Driver Deluxe to play with.
My Basses are a Schecter Elite 4 string with EMG's on it that has good articulation and cuts through the mix well and my Ibanez SR-500 practice bass has active bartolini's and I like the clarity of the sound but the bass has terrible articulation.
Now that I have hopefully given you a idea of my gear and tastes what would be some good pickups for the cheap fun headless bass ebay item# 360140813562?
And also both of my other basses.
Sorry this is so long I just havent spent anytime with pickups of effects in anyway and I feel that it is time.
Thanks Steve

[wtf_is_a_bass]

-P pickup is the typical pickup you would find in a fender precision bass. They are basically a single coil pickup split into two, therefore working as a humbucker
-J pickup is in a typical fender jazz bass. They are single coil pickups and are typically set up in pairs.


If you look them up pcitures of these basses, the pickups are very distinct. They also give completely different, distinct tones.
There are also very useful stickies at the top of the pickups and electronics page that are worthwhile having a look at.