Originally Posted by Dozhdbog
PE can also stand for "Performance Edition" (same two initials), just as LSD can mean Limited Slip Differential and LySergic acid Diethylamide.
I would never confuse the latter two in a BMW forum, but the former two, I think, is easily understandable.
I am also quite familiar with the PPK stages. I went through a lot to get the stage 2 installed in my non-sport 335i.
It seemed like you were confused in your post, but nevermind - I read it out of context. Was the Stage 2 worth its money in your opinion? I've heard mixed reviews.