The best bang for the buck as far as weight goes which if you think about it is stop eating McDonalds, KFC and all that other rubbish. Loose weight which lowers the Fulcrum point and weight to power ratio and you get to spend more money on devaluing your H2. Why do you think the Jockeys in horse racing are so light? The horses go faster that's why.
Check the difference in weight of standard over carbon fibre, calculate how long it would take to loose the same weight, ie, not eating between meals and the math will show that all the weight saving bling offered is just to get your hand in your wallet.
Want to go faster, just flash the ECU (and get your BMI under control), best bang for the buck.