Karl, it's all about each ECU's method of idle control, processor speeds and so on. Some run the car nicer than others. Some tuners get on better with some ECU's than others too.

I always tend to advise to pick your management based on who will tune it. Let them have an input. There are various ECU's we won't touch, but only based on past experiences. There are also some that we do that I know others have given up with.