MIM Jazz Bass Query (buying used, some advice)

Funkfingers

IMHO, P-style and Overkill via balance pot is the way to go. Be thankful that the BCRS’s J pickup rout is not in the Norman Watt-Roy position.

Creed_Clicks

Would love to hear some sounds samples of the overkill 

Stratavarious

You can wire the pair of jazz bass pickups in series rather than parallel and you get a lot of the precision thump and bottom extension.  I have made mine switchable for that and it stays in series nearly all the time.  Really is a best of both worlds solution.

prowla

Just beware of fakes, inc. Squiers "upbranded" with a Fender logo.