Arn't you worried about rocks from the tires pounding it?Alex,
I'm doing the same as Jack; 22.5" extensions, Port-side differential cooler, Starboard-side engine cooler (engine cooler has auxillary blower).
pics would be helpful of the rear location (if I could remember where I saw them, lol!)I'll have a stainless mesh screen covering the opening and the engine cooler has an extra mesh cover as well. You can alternatively, place the coolers at the rear as you mentioned.