Okay, this notice is for installers of a 2006 F-350 Dual Diesel 4x4 only. A standard mounting bracket is all you need. Do not use the spacers provided. Either medium or high distance mount. Initially it seemed I would need a center brace to hit the axle. But he clearly didn't fit the space. Although there was a 1/4 inch gap with the support bracket, inflation of the airbag eliminated this for a perfect fit. I spent about an hour installing the center bouncer spacer due to the 1/4" gap but was unable to mount it. All in all, this is a great kit for a 2006 F-350 with a dual 4x4 diesel engine. I use 40 pounds of pressure from a bike pump or my 12k saddle bike and it makes a world of difference! one and about an hour for the second on the way.