I believe BMW didn't do Valvtronic because of how high this motor revs.
It's used in most of the non-M engines... oh wait, all the other engines are now non-M engines since they're based on the N line with the boost turned up.
Let me get this straight... You are swapping out parts designed by some of the top engineers in the world because some guys sponsored by a company told you it's "better??" But when you ask the same guy about tracking, "oh no, I have a kid now" or "I just detailed my car." or "i just got new tires."