I have a US Gear D-Celerator remote brake. Love it. I did the air operated one to avoid the dc selenoid problems you can have with water etc and elec power.
It is a VERY substancially built unit. Heavy castings, large bearing surface for the main butterfly, has a seperate port bypass based on backpressure, joint gasket comes with it to insure a good seal to the exhaust manifold. Whole system is built to insure a full 4" flow when open.
I love it. It works really well with the speed control and DTT Smart Controller as a whole integrated system.
Make sure if you have an auto you do some kind of a lock up controller.
If you have an under/over drive unit I think that an exhaust brake will not work with a GV due to the design of the clutch system in the GV.
Bob Weis