I was planning on buying a good used Mexican Jazz Bass and switching the pickups on it. I want a warm, but tight and focused sound. For an example, I like Tim Commerford's tone on the Rage Against the Machine song "Bullet in the Head". I am very much leaning on going with Bartolini pickups, cause i like their warmth and "frown" EQ tone curve. For an example of a sound I DON'T want, listen to the Duncan Quarter Pounder pickups. Not warm enough for me, and the P-bass one distorts the preamp!!! I welcome any suggestions or death threats , particularly dealing whether or not to go with the Barts. Thank you.
Have you checked out the J pickup shootout at the Bass Player mag site? (well, now part of the musicplayer.com site) It's in the "Gear" section on the right hand side when you scroll down. Barts are a good choice because they are noted for being very "natural" sounding. You'll probably see some comments about Basslines that will catch your attention, (excluding the Quarter Pounds).