alright so i wanna know if NGK iridium plugs are good or not, i keep hearing there bad and than there good, i hear they will mess up your coil pack or give you good gas mileage, so i have them in my car and from day 1 i ran 94 sunoco, today i went to niagra falls and back going speed limit and my ECO was at 7.8-8.2l/100km need less to say I got HORRIBLE gas mileage, i went 450km in total and by the time i got home i was on redline. now i have the raw 3inch CAI and i had oil changed a week ago and my air filter is pretty much new. is it the spark plugs?, BTW this is pure highway driving at 100-120km/h

anyone!!??