A few weeks ago I bought a CIJ '57 Precision via this very forum, and expressed my delight [url="http://basschat.co.uk/topic/287183-nbd-and-a-tale-of-4-string-sets"]here[/url]. Over that time I became somewhat dissatisfied with the sound, in particular when I gigged and rehearsed it with my country band. Frank Zappa famously said that talking about music was like fishing about architecture, but with that in mind caveat I think the stock pickup was a bit lacking in the fat mids that I crave, and quite smooth-sounding. On the one hand I didn't mind that it sounded different from my other Precisions, but on the other it wasn't quite in the ballpark for me.
Anyway, I bought and fitted a Fender Custom Shop '62 pickup. Fortunately the dimensions are exactly the same, so no routing, drilling, sawing, or filing were required, although the larger screw heads on the CS unit meant I had to jiggle the aly scratchplate a bit to get it back in place.
And what a difference! My £550 bass now sounds like a £1,000 instrument. It's not a million miles form my '63 RI, with loads of punch and growl, and all the range I want across the travel of the tone control. This is a 'spare' bass that will now hold its own with my 'main' basses.
The Fender blurb describe this pickup as having 'flush' pole pieces, but in fact they do project through the covers (although they are not staggered). I don't know whether this is period-correct for a '62 (and I don't really care, as it is on a supposedly '57 bass), but it might put some people off as there is always the chance of catching your fingers, pick, or even strings on the pole pieces.
As always, pics or it didn't happen: