What I've learned from this discussion is that I should probably leave alone my air intake and keep the single air filter housing design. I will change one thing though - while researching these air coolers I discovered that both CAT and Donaldson now make a new line of air filters that use some special fiber called 'ultra-web'. These filters are supposed to provide more air flow and they also last longer. Donaldson: EAF5069; CAT: UHE air filter. Both of these interchange with the regular Fleetguard I've been using on my Cat C15. I called Traction Truck Parts and - surprise - the guy said he had the Donaldson filter. They are a tad more expensive than the regular ones, but I think they're worth it... I'm just waiting for my current Fleetguard to kick the bucket