Hello everyone. Brand new to BMW. But I've been installing car audio systems for like 10 years. But with this car, all I hear is how different it is. I do not have Idrive. I have the hifi professional option in the car. It's a 2007 335i. I would like to install my amp and 2 12" subs. In my speed6 I soldered together my own LOC and tapped into the factory sub wires. And everything was cool. Not sure if I can do the same here. But I really want to install a double din headunit, retain steering wheel controls, and have the jb4 app on the unit in order to monitor, run codes and what not. How many people successfully do this without compromising anything?