Everything on Roundel for the last few months has said the next M3 will have a turbo I6. It'd also been said BMW believes the ideal cylinder size to be 0.5L; thus is especially true for the M division, but who knows with Segler running the show now.
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."