Make sure you don't build yourself a HAI (hot air intake) Doing some searches will show you how not to and why you shouldn't.

 

look at my profile, i have an example of HAI, no longer in my car but theres examples i believe or i have posted pics at least

 

i too have an ls and been kicking around the idea in my head is it possiable to make a sort of ram air like that of a 69 olds w-30 option.but using where the fog lamps should be but remove the "vents" there and run hoses right to the intake. or even use the foglamp holes to run a break cooling hose.