Looking for HD manufacturing and so far the best I can find is www.roambuilt.com
but they are not in full production yet. I saw their equipment at last years OX in Flagstaff and it was really well made. Just an FYI.
The vent above the stock bumper for cooling must be kept open or re-direct air flow to accomplish same. MB and I had a long discussion about this concern, so I am liking the Roam built as they are working closely with MB, especially on the air bag concerns.