Mike Dirnt interview:
From Guitar World: "On this record (Nimrod), I used Precision basses because my old Gibson G-3 didn't sound good with the new songs. I used a '66 and '69; they have a real warmth on the low end. For this record I knew we weren't going for the huge guitar sound; this gave me more room to get in there. I needed to play a real punchy bass on the old records because the guitar frequencies where everywhere and I needed to get right in the middle. I recorded Dookie with a Percision bass too. I use Mesa/Boogie amps, MB 2000's. They're half-tube and half-solid state. I wanted to custom-make my own sound , and Mesa/Boogie was really willing to work with me. They made me 6x10 cabinets, and we put those on top of a 1x18. I think i'm nailing it. I have an MB 2000 running each one of my 6x10 cabinets and then a MB 2000 running both of my 18's."
In any case, both the Precision and G3 are very versatile basses, and are both capable of many different tones on a recording depending on how you set them up, dial the amp/speakers, recording techniques, mics, mic placement, DI, balance between mic and DI, pre and post EQ, etc etc etc