Would that be worth it? A wrap could induce corrosion underneath it , true - but that could be solved with painting the manifold with heat resistant anti-corrosive paint (containing zinc as far as I know). But then, what are you trying to achieve? For reducing the over all under-bonnet-temprature it should be good, but if you are trying to protect specific components (for instance the brake master cylinder) it might be easier to shield that component with some reflective metal. Concerning the under-bonnet-temperature, would reducing it improve performance? Well, it might a tad. Would you notice? Most likely not. Is it fun? Definately yes, and of course you know the difference between boys and men. As for how to wrap, there are plenty of movies on youtube.
2004 V6 Roadster