I'm going to disagree on the basis of my SiR. I didn't make any power when I added a CAI (off a VTiR hatch- dummied up with conduit) even though it was pulling air from under the front bumper. This is compared to a Jamex and a Finer Filter (custom made) insert. Both saw equal gain. Now the SiR has a snorkle that pulls air into the box from the front of the car, not from the side so that might be the difference. This was tested on a dyno, so it doesn't really apply to the real world. We flow tested the filters - CAI was 10% better flow over the stock filter, Finer Filter was custom built and flowed 7% better than the standard filter and the Jamex flowed 7% as well. Is 3% worth the money? No IMO.
The car mentioned in the original post was a '98 Accord - I'm guessing with no other mods. In which case a CAI is not going to give you a noticible increase until the rest of the engine is breathing a lot better. You will not notice any improvement with a CAI other than it sounding louder. Even if you get 3-5bhp (*cough* bullshit on a stock Accord), that is at the flywheel. Add in drivetrain loss and it's not the best use of money.
I'd go the K&N and put your money into something else for the car unless you are planning to really work on the car's breathing
Just my $0.02
