While doing research on the stock airbox mod, I looked at a lot of different ways to mod the box. I have some of them listed below. I decided on a simple plan that would allow a lot of air, without being obvious.
N2TRUX
Ayrton
BAD 2DA BONE
Since some people want to take this as far as possible, I have a second set of threads that list those that ran fresh air intakes to the bottom of the box-
Captainoblivious
Blackhawk
Of course this would not be complete with out a link to Tim Skeltons site. Here is his page about cold air intakes. This is one of the best user sites I know of, so spend some time looking around-
Tim Skelton
Here's some recent data concerning intake temps. These two threads discuss the difference in intake temps using various types of air intakes-
Crockett59
Ken800