Just removing the snorkum thing in the right fender also makes a big difference. I ripped that puppy out earlier this week and was impressed what a difference that made. The engine revved much quicker and easier than before and sounds great at high rpms. Feels stronger all in all, according to model 170lb buttdyno. Downside is that repolacing the inner fender liners/covers will require a trip to the dealership for additional clips, etc. as removal was a pain.
Will probably need an S-AFC once my JC sport intake comes and I install it with a cold air intake adapter (have a '99 RS). Where is the best (ie cheapest) place to get an Apexi S-AFC, in you all's opinion?