I'm using a Spal #2052 and I'm pretty happy with it. It pulls 2780 cfm at 25 amps and fits really nice on the 22" champion with minor mods.. The water pump snout fits between the two fans with room to spare and there's light rubber flaps on the shroud that open up at anything over about 25 mph and allow air to pass through.
Mines wired with one fan on a controller for use in most circumstances and the second fan on a switch on the dash for stop and go traffic when the temp usually starts to creep up.
It is kind of loud, but can only be heard when the motor isn't running.
http://www.spal-usa.com/fans/automated/tech_sheets/2052.pdf
