I did a DIY icebox, with a K&N E2427 drop in filter. With the removal of the resonator the intake noise has increased somewhat.

Here is the exact DIY I did. There's pictures there so you can see the
icebox setup.
http://www.geocities.com/bretq/DIY_Icebox_CAI.html

I've been considering the Comptech icebox myself though. Comptech products rock. :thumbup: