I just installed the SP Diesel about two weeks ago and it works great!!!! My first big test drive pulling the trailer was over the Grapevine between Bakersfield and LA. It's a pretty good grade and I came down it easily without having to use the regular brakes!!!! With the exhaust brake engaged, I maintained a safe speed by just taking the truck out of OD!!! That was not the case without the exhaust brake, I have done that a couple of times!!
Our next big test will be north to Alaska, and I feel the exhaust brake will really make the trip easier and safer, and equally important, my co-pilot thinks so too!!!
The install was also pretty easy, and for me to say that, it would be a breeze for most (this was my first install of any add-ons). I had four wires to splice and a couple of plug-ins and I had never used splices before.
I'm happy with it!!