header wrap on stock exhaust manifolds?

i was thinking may wrap my exhaust manifolds and pipes around the firewall to reduce temp in eng compartment and maybe make it a lil bit quieter with the header wrap stuff . does that stuff really cool the engine more like it says? plus i want to maybe make them look better then the ugly rust that is on them its called header wrap but it will wor4k on ex manifolds right? just wondering how to make the engine looks and be cooler.