Banks speed brake
 

Has anybody installed one of these on a 07 or later duramax? I'm think of adding this and would like to get some feedback.

I had one on a 7.3 powerstroke. It was a help with towing but mine actually went bad so I just went to the power elbow. I really don't tow much anymore so I had no need for it. If you tow alot around hills or mountains I would say it is a huge benefit.