I installed the Jake brake on an 03 Dodge I bought new. Doing the install isn't that bad if you are at all mechanically inclined. Maybe 5 hours work. The 06 I have now I bought used, and it already had the Jake installed.
Comes as a box full of all the parts, for like $1200 from Dodge, and I'm told several hundred cheaper at the Cummins parts house. I believe the 48RE has to have a controller added to keep the TC locked up, but my trucks were both stick shifts, one with the NV5600 and the G56 on my current truck.
There have been treads about the vacuum pump failing, and the previous owner of my 06 had the vacuum pump replaced under warranty. I've had no problems with either Jake setup, but it does seem funny to me to have such a big belt driven vacuum pump just to run one little actuator on the actual brake.
The exhaust brake feature of the variable turbo on the 6.7 is extremely effective with either the G56 stick, or the 68RFE auto.
Anyhoo, if you decide to install the Jake yourself and have any questions...
Dodge 4x4 dually quad cab, 6 speed with jake, B&W Companion, Brakesmart.Patio Hauler 5th wheel Toyhauler, Foreman, Rincon, R1200GSA, Roadking.