Bladerunner, you can get comair rotron fans in the UK from
www.rswww.com, they aren't cheap from there though. I managed to find a used 235 cfm 172mm model for £5 though. Wish I'd bought 3 or 4 of them now.
Cathar, how'd you get the bus high enough for that sort of speeds on a 2500+? Or is it unlocked?