frozenboost.com/siliconeintakes.com sells cheap ($30) slim fans in different sizes.
Save yourself the hassle, because of my manifold and mishimoto radiator I needed slim fans, at first I went the ebay route that = overheating cause the fan sucked, I've tried several"inexpensive" fans and still overheating issues, so what do I do? STOCK FANS STOCK RADIATOR FTW...done!