The oil pans ability to dissipate heat IS diminished, especially by thermal barrier tape, so I did not cover the entire pan, just the area next to the closest header pipe at the front of the pan.
I did it, it worked. Saw much lower oil temps at the track.
The Tomei supplied tape I believe is a thermal barrier, I used gold heat reflective tape, (It's only temporary for now, I'm going to a jet engine thermal barrier plate between pan and pipe, not touching either).
I believe the Tomei tape retains more pan heat than the gold tapes non thermal (just heat reflection) tape, so IMHO it would be prudent NOT to cover the entire pan except in the front only, and leave some pan surface free.
CERBERUS