I posted this before - but since you asked-
I have a 2011 135i with the PE and the PPK. The before is stock with PE and the after is PPK and PE. Before 270.5 hp 290 tq. After 294 hp and 336 tq
This was on a Dyno Jet
I am very pleased with the PPK and the PE. They are a great combo. The sounds fantastic and the power is a noticable improvement. However, it is an improvement and not a transformation. If you go into it with that expectation I think you will be pleased.