Time For A Tune Up
The plugs may be hard to loosen the first time. You should put antisieze on them so the next time you have to change them they aren't so hard.
In addition to the air pipe, also removed the front 3 coil packs on passenger side only (I have a 98 too). My plugs were so tight I had to use a 3/8 drive swivel tip breaker bar with a cheater pipe for extra leverage. All cracked loud when they finally loosened, I was surprised I didn't break any. However others have said theirs were not overly tight. Mine still had factory originals at 50k, and I have to say 100k plug life is massive BS.

