I finally got around to making a cone filter intake for the '04. I used a large 6" x 9" K&N filter and a few pieces of plumbing parts to build it. So far I'm pleased, noting at least a small performance increase along with that satisfying blower whine!
This is not a cold air intake, but I decided to make this first before trying the FWI. Tests I've made in other cars with underhood cone filters indicate that usually after moving 50-60 feet the intake temperature drops to close to ambient anyway, at least up here in Alaska summers. In truly hot climates a fenderwell intake will likely be better.
This one replaces the restrictive corrigated factory tube between the TB and the MAF sensor, giving a straighter shot from the filter. Combined with the large filter, the pressure losses for the intake will be very minimal. I'll see what the true performance advangate is at the track this weekend.