I recently bought a GK MB Fusion 800 and although I really do like it, I'm beginning to get convinced that the TH500 is the sound for me. I'm hesitant to lose any headroom, however, as I play in an extremely loud instrumental rock/fusion band, competing against a guitarist with a 100-watt tube head and a 4x12 cab. I've heard that the TH350 and the MB500 use the same power module; is that true for the TH500 and MB800 as well? If so, is one still louder than the other? I'm playing a fretless Zon Sonus Custom 6 through a Mesa PH212 8-ohm cab if that makes any difference. I'm going to add another 2x12 at some point, but for now all I could really afford to do is trade heads. Thanks for any advice.