If Jethot's thermal-resistant properties are as impressive as reported, then coating the intake manifold may actually be worth it on a non-crossflow design like the OM617. On my OM603 w/mid-size intercooler, I can place my hand on the intake manifold after a hard run (with good high velocity airflow over the IC) and it's cool to the touch (ambient or lower), so Jethot probably wouldn't be as necessary. It might help to avoid manifold heat-soak during stop and go traffic though.