We have the Ultra Guard. Used 2 strips of heavy guage metal (one on each side of the UG) instead of the angle iron. Then used ordinary hardware to hang it like the diesel pushers do.
We had the Banks Power Pack installed but have not had an opportunity to fully evualate it. On the drive home over a fairly steep grade it looked very promising.
Would now like to find the Banks Ram Air kit and will keep following the Ultrapower opinions.