hello.
a.) It's 135 watts...valve watts mind, so they are perceived louder than solid state watts.
b.) Yes it is giggable, I practice with 2 guitars and a drummer with preamp on 10 and master at 3 or 4.
c.) Not sure what you mean about the 2x12...I'm running a 4ohm matamp 2x12, but it's not for sale. This is for sale for 400 collected.