I dunno, my intake with Home Depot parts (Named Porterized by someone else!) that I did about 13 years ago is about the cheapest way to get about all the air that you can get into the stock airbox. With a bunch of other little changes, it made my '99 the first gen 3 into the 14s, followed by a few other folks (Ian, Paul Nimz, Ryan Dudek) with basically the same mods.
As we've learned, this stuff just nibbles at the edges. But, to do the other stuff that the Gen 1/2 guys have done (turbos, s/c), there is the tranny and cooling issues on a Gen 3.
Although Carter and Eric Lehmann (E1 above) have put s/cs on their Gen 3s. Plus another setup done by someone out here by Doug Lewis, but I believe that car has been put back to n/a.