hi I would like to switch from my bass combo to a head/cab setup... but I'm a bit confused. It seems that most cabs have 8 ohm impedance and many heads aren't so powerful at 8 ohm... My combo is 350 w at 4 ohm (the cabinet is also 4 ohm) so I would like to get something more powerful... what should I buy??? I don't know much about bass heads.. I saw on the ampeg site the svt3 pro it seems nice but at 8 ohm it goes for 275w.... is it enough???