Get a 335 and tune it. You'll get 400whp with a tune, down pipe, intake and exhaust. Though you will need some race gas mixed in.
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."