Depending on how well you are looking to insulate your Car from Heat and Noise, I think I would consider a combination of products, such as Lizardskin, Fatmat/Dynamat for the Insulative properties, and then anti-flutter Foam for the Bows (to stop noise and vibration)-

Here is one Anti-Flutter Foam (although you will need an Application gun), although there are many different Compaines offering them-I personally like Lord Fusor the best, but....

"3M™ Automix™ Flexible Foam is a soft and flexible two-part urethane material which foams in place (closed-cell foam). It is designed to replace OEM's flexible foams found on door intrusion beams, roof bows, inside body panels, and in other automotive body cavities. This flexible foam expands to 10 times its original size. Foam time takes 40 seconds, work time is 5 minutes, cure time is 1 hour."

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Here is the Lord Fusor product-

Ketone.com: Lord Fusor® 10.1 oz. Super Flexible Anti-Flutter Foam, Fast Set Formula, Foams & Sealant Products, LF121