Ok, so here's my situation. I love, love, love my '10 Mapleglo 4003 but two things drive me nuts:
1) Single coil noise. Lots of venues that I gig it accentuate the noise to an unusable level due to many factors, one of which is that I remove the bridge pup cover (I'm a fingerstyle player, and anchor my thumb on the bridge pup itself). I'm not putting the cover back on.
2) No master volume/tone.

I'm thinking about remedying both of these issues by installing a pair of HB1s and switching the wiring to master vol/ master tone. I don't care about the "vintage tone" cap pull-pot, as I never use that setting. What do I need to be aware of when installing these pickups? I know that I need to upgrade the vol pot to 500K. I play with flats, so will that still get a Ric-approved level of high-end? Will I have to modify (i.e. drill) to make these pickups fit?

http://www.rickenbacker.com/forum_view_ ... Humbuckers for 4003

Check out my thread (link above).
I think it is currently on page 4 of the 'Just Basses' forum.
Cassius has hb's on his 4003.

Personally, I'd opt for selling the 4003, and investing in a 4004Cii. I have one of each, and always play the 4004 as my #1, just keep the 4003 for when I really want the single coil sound. The 4003 sounds like it does, noise and all, because that's how they've always been. If you didn't want a single coil bass, the 4004 is an obvious choice.

4003's play so much nicer than 4004's since the 4004 's neck has a much wider taper, so, depending on the size of your hands, changing basses may not be something you want to do. I've never found Rick's single coil pickups to be particularly noisy though. Are you running all your gear through a power conditioner? Do you have a lot of treble dialed in with your sound? I've got a pair of HB1's installed in my custom 8-string Rick with the tone controls wired as coil taps, so I have the best of both worlds, but I don't get much hum in single coil mode at all.