Dodge Caliber Performance Mods, Engine, SRT4
The spark plugs that are in the CSRT4 are platinum. I have no clue why dodge did this, as we know, platinum and turbo's are not really a good combination.
The replacement Iridiums are Stock number 2477 or Part number ZFR5FIX-11 which you can purchase from sparkplugs.com or maybe go to a local...