I have what may seem as a dumb question but what is the purpose of an exhaust break? And another is what is a stand alone controller? Seen em both but haven't done much research on it.
As stated above, the exhaust brake allows the engine to slow the truck. It is not really needed if you are not towing. I never had one, but i was not towing REALLY heavy, I maxed out at about 8K behind the truck and just used tow-haul.
As for stand alone controllers, it depends. I know the ATS CoPilot sends an output signal to a unit like a PacBrake that will turn it on. The CoPilot will keep the converter locked when the exhaust brake is ON.
Banks may do something similar with their controller unit, not sure on that one. I do know that the Banks stuff, while really good, and expensive, does not play well with others (non-Banks). I'm not ragging on Banks, I used to run one of there 6-guns, many moons ago.
Unless you do a lot of heavy towing, I would say it is not worth the trouble, and if you want performance, you do not want to have any additional "stuff" in your exhaust system....especially if you are running sooty tunes. I think that would cause problems over time with the actuation of the butterfly valve.