I have a small 17 ft CC I usually tow it with my F150 w/ Triton V8 withtow package. My wifes car is a 2004 V6 Nissan Exterra The manual says towing capasity is 5000 lbs but recommends trailer brakes for anything over 1000 lbs. Two questions, Should I add a Tranny cooler and are brakes really...