look, I played an outside gig a while back and and all I used was a 50 watt Peavey Classic 50 2x12 combo, and it was PLENTY loud. The vocal's were the only thing that was mic'd. Trust us! The 100 watt Marshall half stack will be PLENTY loud!

If you mic'd your amp, everybody else would sound really dull. So, to make sure everything sounds right, don't mic your amp.