Listen to bio, and save money. I don't know the exact thread pitch on the o2 bung, but they make spark plug no fouler at your locat auto parts store. You just need to get that and install it, not an emulator. Once this is done you will not throw a check engine because your front o2 is sending a certain amount of resistance back to the pcm. When you raise the back o2 it reads less exhaust gases which tricks the computer in believing there is actually a cat there so the o2 has less resistance back to the pcm. Your only problem with emissions is the fact that they use those little mirrors under your car to check if you have a cat installed.