Regarding the head vs. rack setup: It would seem to me that a simple preamp (T21 RBI or otherwise) over a simple poweramp (insert QSC model here) would offer more options (and power) than a standard head (lets say GK1001 or SVT4?). On the surface, it would also appear to be more affordable (and expandable). In a band situation, that power amp could be used to power additional monitors (or something else) dependent on what you discover is available to you when you got to the stage. Am I making sense here? Would a separate preamp/poweramp alone rival the performance of a standalone bass head? And then offer additional useage options over and above the bass head alone?