Cheers guys. I've wrapped the exhaust manifold with notable improvements. In doing that I've also noticed some of the external ceramic coating fall away. (Note to self-wear gloves next time)
I've had a small section of the crappy ebay lining stuck under the bonnet right on top of the manifold for a bit over a week and no signs of issues. So I've ordered some black sound deadener material (250deg temp rating) to line the underside of the bonnet. I'd say it's problem solved.

But that ACL shielding has me looking for other applications..hmmmmm. Looks like good stuff. Thanks.

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MY00 WRX. 89 Prelude. 99 CRV