I had a Fender Custom Shop "Vintage Precision Custom Bass" model. It was loosely based on a 55 P -- i.e. 51 style shape with contours added, still had the 51 style pickguard and two-saddle bridge -- yet it came standard with a P/J setup and concentric knobs. It was a beauty and it sounded great, though I eventually sold it because the neck was just too big for me. But if I posted a pic without telling you what it was, some of you would rag on it just because it doesn't look exactly like the originals.
Doing something different doesn't make it bad. It's an instrument, not a work of art. If a different set of pickups give you the sound you want and your workmanship is good, I see no problem with modding.
