Phenolic intake manifold spacers?

[Thai-wronghorse]

I was just doing my usual mooch around eBay for ARL bits and pieces when I stumbled across these phenolic spacers which supposedly bring down intake air temperatures by isolating the cylinder head from the intake manifold.
Has anyone have any experience of them or opinions?

Look at this on eBay http://www.ebay.co.uk/itm/172359015785

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[cheshire cat]

I would have thought a waste of time on a diesel petrol maybe