performance wise, iridiums won't really get you anything. spark plugs odn't get you anything unless you got some other performance mods that warrant a "better" spark. they will last a whole hell of a lot longer though. it seems some trucks like them some don't, and it's not model specific, it's truck specific.
if you put iridiums in and your truck doesn't hate them, you'll never change plugs again.

 

alright thanks. if its only about longevity, then NGK coppers are going back in. id rather not do plug changes once a month because my truck doesnt like that plug. my truck ran fine on the NGK coppers and putting them back in wont be playing a guessing game

 

+1 on the NGK coppers. I run the V-power copper plugs in my Mustang. The Hemi is too new yet for plugs @ 2500 miles.

 

I've looked into The Iridium vs Copper debate. In my situation cost is an issue and if my engine won't benefit from the iridium plugs why pay for it.

Based on what I've been able to determine, If your not running a high performance engine then the copper / stock plug is the way to go. Just make sure to replaced regularly. It does appear to be true that iridiums provide a hotter spark and more power when ran a Supercharged engine, but not in a stock engine. So definitely not worth the extra dollars also iridium may not last as long as coppers and they cost twice as much.
also I don't know if this is true but read , that " iridiums fowl entirely too easy."

 

Stick with OEM plugs. Its one thing to get different brands, but at least get the equivalent plug. Using different plugs is a great way to make a perfectly good engine run like crap. Not everything that is aftermarket or "performance" is better.

From the 2004 Factory service manual: