The wrap will definitely rust out the headers much faster than normal. The Aluminum heat shield would definitely help. Perhaps you could wrap your Brake lines with this: Heat Shield Wrap
It's supposed to reflect up to 95% of the radiant heat.
You could also cover your heat-shield with this
Lava Mat, volcanic rock heat-shield. LAVA HEAT SHIELD
It looks pretty trick and it would improve the performance of your proposed heat-shield.
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