£200 is $380US...could build a mighty impressive kit with that amount of money. Just as it's possible to tweak a wb for a single point test, it's possible to tweak a kit for this contest. If I wanted to win such a contest I think I'd go to Cooltechnica and equip a kit with 2x Black Ice Extreme 2s, 4x Delta high power 120mm, a D4 pump, and a MCW6000. Should fall right around the max price. Lowering water temps would be the way to win a "kit contest".
My solution is loud as hell and wouldn't fit in any normal case, but it'd be cool