The best insulator is air. The biggest hurdle with our intakes is the proximity to the cylinder heads and lack of a vented hood. On mine, the tubes are almost touching the front coil packs. After shutting off the engine the radiant heat gets through the material regardless of all the testing claiming otherwise. I wrapped my headers with the best wrap I could find with no change. As a matter of fact, every single thing I've done to cool the intake charge has had the same double effect. Longer to get up to temperature, reaches the same temperature as before, much longer to cool down. This includes the thermal coating on the intake manifolds, thermal coating on the I/C, the wrapping of the I/C in addition to the thermal coating, the wrapping of the headers, the wrapping of the intake tubes, etc. In other words it'll help a bit for a couple of runs down the dragstrip. Extend your cool down times between runs. Thats about it IMO and experience.

Les