To give any aripump a bit more umph as you call it, have you tried making a ring main out of plastic overflow pipe and some 90 degree bends. Drill a hole for the airline at one side and attach the airline from the pump, then drill another hole in the far side if the ring and attach the airline to a gangvalve and this will give you alot more air output.
I just bought a Penn Plax X5 for my 90 gallon tank. I only ran it for about 10 minutes last night but it seemed to be relatively quiet and it had no problem with a 15" bubble wall and 6" air stone in my 24" deep tank. It has two settings on it too, one for less power more quiet and one for less quiet more power. Didn't seem bad for $20 US.