I agree it probably doesn't matter which way your flow goes, but just in case I'd probably give Griffin a call and ask them if they had anything in mind for the inlet/outlet fitting. Never hurts to talk to the guy who designed the product. From the Griffin website -
For more information on our products please contact us at: 1-800-RACERAD or (864) 845-5000
(Griffin believes in customer service, your call will be answered promptly by a member of our staff located at our main production facility in Piedmont, SC)