I have been running a FF Dynamics's 3000-3500 cfm big single electric fan ( NOT the smaller dual set up ) with housing and thermostats $300.00 on EBay and it's just been perfect !
I have had it on for a few months and put over 4,000 miles most of which have been desert rocky washes, long hills and mountain off road trails. So. Cal people might know the areas I go to, Afton canyon, back side Calico, White mountain, Death Valley. I live at 7,000 ft in the mountains so I deal with a lot of long uphills on the pavement also. In the desert we still deal with 100 degree heat and mid 30's mountains at night. I just love loosing the fan noise !!
Anyone in the area want to go just yell, but we will warn you. If you drive a show VX, don't yell at me if it comes back looking like, like, mine.. lol