I'm considering racking my Shuttle 6.0 and using it as a pre along with a QSC GX5 (which I already own). In a two, 8-ohm cab situation I'd have almost double the power (1Kw vs. 600w). Arguably, the type of power amp would/could make a diff as well; Class D for the Shuttle vs. Class H for the GX5. The power amp might also have better control over the cab too. All hypothetical/guessing on my part, obviously. I'm curious about what differences I'd hear and feel as far as "bite/oomph/thump" go. It's difficult for me to test at home b/c I live in an apartment...no cranking anything up at home, unfortunately. There's at least one user here I know of, but can't remember his name, that does something similar. He's got a Shuttlemax and a PLX3602 *drool*. Anyone else? I'm really interested in hearing your experiences and thoughts. If the GB folks would like to chime in, I'd love to hear from you too.