What is the best fan to put on a Swiftech MCX4000?

What is the best fan to put on a Swiftech MCX4000??? What size can I fit on it????

From what I can see you can use fans up to 92 mm, so you should probably use either a smartfan 2 or either the 80mm tornado or the 92mm tornado. If you want something quieter then you could probably get an aluminum 92mm fan that gives good cfm with low noise.