UPDATE HEAT SHIELD INSTALLED
Just installed some heat shield. I use a product called Reflectix: Double Reflective Insulation that i bought from Home Depot ($25 for 50sqft).
I read a bunch of reviews from people on the Corvette forum who seem to have had very good results shielding the cabin from engine / exhaust and transmission heat.
http://www.homedepot.com/Reflectix/h_d1/N-5yc1vZ1xr5Z19n/R-100052556/h_d2/ProductDisplay?langId=-1&storeId=10051&catalogId=10053
Reflectix is very easy to work with and I with help from dear ol' dad managed to get the firewall, transmission tunnel and cabin floors done in about 3 hrs (Start to finish). I used 3M super 77 adhesive and Aluminum foil tape to stick and secure the Reflectix.