I posted this on another thread, may be helpfull to you.
The intake air temperature significantly influences the horsepower output of an engine. For example, if an engine's intake temperature was dropped from 110°F to 75°F, then the change is horsepower is approximately +7% ( -1% @ 75°F minus -8% @ 110°F). If the engine normally produces 200 horsepower, then this 7% increase in power translates to about a 14 horsepower increase. Achieving the lowest possible intake temperatures is therefore very advantageous.
Anything you do to reduce temps is good. I agree with Scotty, the reflectix material may be better. Wizaired uses it inside their boxes. Also is your cone inside the fenderwell? If so do you have a blockoff plate so the tube fits snuggly going into your fender? You want to keep those high engine temps from being sucked into your intake for the most benefits.