I have just been re-doing mine, using
this material. Interesting claims about less vibration transmission than silicone, and I quite believe it.
The gaps visible in the pics do actually close up perfectly when the top cowling is on - this was verified with photos.
The CHTs dropped a good 10F, so that was well worthwhile.
I have thus far re-made just the
top baffles; the bottom ones will need a hangar.