Well today I finally got around to installing the plugs. The installation was a breeze. The only thing that stood out was the fact that the ngk plugs had shorter threads then stock but they screwed in fine. When I took the car for a spin, right off the bat I noticed the lower end of the RPM band increase ever so smoothly.... no studdering or hesitations like before. On a negitive note, I noticed that when I release the throttle at say 4k+ RPM it make's a loud ass pop sound as if it's back firing or something. I noticed it before the install but it's become more excessive now. This sound is starting to worry me, I'm afraid I might mess up my cat or worse. I'm running bigger injetors with no AFPR....I haven't got around to installing it yet, and I know I'm running rich as I have a CEL for too rich.
Any insight would be greatly appreciated.