I changed my plugs to NGK Iridium's IX.. I didn't really think i'd notice any difference...but...It actually has been a pretty good swap. I noticed more zip to my accelleration and the car seems to be more fuel efficient. Although I did just get an oil change too...As far as how much more gas mileage I'm getting..I'm pretty sure its minimal or barely noticeable..Maybe its all in my head!! But i swear its not burning as much gas as it did with the the OEM plugs in..

Anyone else using some good plugs and noticed any difference after they were installed?