On the fans... a lot of the generic aftermarket fans are pretty feeble. You would need two really high end (expensive) 12" fans to get the job done. I'd think you would need at least 5000 rated CFM.

If you can adapt an OE type fan much better value and more effective. The Chevy HHR fan is supposed to be good and the Mercedes fan mentioned above very good. 12" (approx) fans were used on some Durangos so maybe look there.