A heat shield definitely would help. JC Aimhigher (John Miks) makes an awesome one. I just don't have an extra 60 bucks right now. I did notice that the intake manifold was hotter...I didn't test it with a guage but you could tell. It really isn't much louder without the liner and not much quieter with it. Mind you I suck alot of air because my battery is in the trunk and I removed all the fron tray sucking air straight from the ground. It is only "noticebly" louder during the opening of the secondaries. Cruising no louder at all.
