Spark plug Denso or AC DELCO

if you're gonna go iridium get the denso's because they (denso) have a smaller tip on them allowing for a "cleaner spark" and therefore a greater chance for detonation....less missfires as someone else has already said....I've run them both and I'm very pleased with the denso's

I did not, and bought the Denso Iridiums. I have less misfires and slightly stronger gas mileage since install. Just my experience.

I like the Denso 3008's I've been using for a couple years now in my turbo.

im using the denso 1k22 great plugs for ko4

I installed the Denso Iridium IK22's a couple of weekends ago, and i love them! They are 1 heat range colder than stock, i changed them out at 30k... The stock plugs were definitely gone, installation took 1hr. After i changed them out, the car ran tremendously smoother, and the car seemed more responsive all together.

After I replaced mk Denso Iridium IK22's with the bosch coppers the problem disappeared. It looked as if the electorodes on 2 of the Denso's were oddly eroded and were probably causing a misfire.

I was useing the Bosch +2's for about 4 months and switched them out for the Denso Iridium's, could definitely tell a difference.

denso iridiums - changed to these a month ago, and car feels more responsive and smoother