Honestly, most people won't see a difference. Most people have only had their cars for about one year max, less have aftermarket exhausts, and even less actually track it hard enough to see high temperature in the exhaust. If there are any problems with not having a shield, we probably won't see any reports until a bit later.
But the heat shield only costs like $40, so why not play it safe?
Lucid, if you could take some temp measurements during a track session, let us know.