Not what I would say a hard install, just those dang connectors are all difficult to take apart and you can expect some hand scraping to happen....
Very noticeable acceleration increase. I think drivability is better and my wife does as well. So far, I would still put it in.
2013 535i xDrive, Imperial Blue Metallic, Oyster and Black Nappa Leather, ZCW, ZDA, ZDH, ZLS, ZMP, ZPP, ZTP, 2TB, 323, 416, 4CE, 4U1, 5AC, 677, JB4 Tuner