There are threads about turtle shells and horsepower but in my measuring it does nothing for temps all about acoustics and appearance. There is sound deadening underneath which can be imporoved on, and there is an acoustic skull cap over the actual intake runners.
Personal preference really if you want more roar sound. I took everything off and bought split covers, only to find it too noisy with my induction mods (RCR Ram Air manifold, ported TB and Orssom). Sounded like an old woman getting the hog at certain RPM and an Owl at idle, so went the other way and re-installed everything with better sound insulation material plus put a sound deadening blanket over the entire engine bay.
That worked really well as a sleeper but looked the automotive equivalent of wearing a tin foil hat, and lack of engine feedback all exhaust sorta put me to sleep a bit as well.
I settled on skull cap and sound insulation under split corvette covers for a unique sound and look that I like.