I'm considering upgrading my electronic setup from my current: upton rev. PU to a sansamp bass driver/DI into a GK backline 600 head into a 4x10 GK BLX cab. I don't have the money for a completely new rig, but could change out a few for the positive. My problem with the amp is that it's SO BIG AND HEAVY. Also, I don't even know if the sansamp works as a good pre, but I've been using it. Finally, I could switch out the PU for a mic or nicer pickup. It does have to be suitable for electric as well though. I'll be using it for jazz, indie rock and church music. What do you guys think will be the most beneficial?