Ok!
Heres the real deal!
Platinum Plugs are colder plugs COMPARED to Iridiums but the BOSCH 4 Point plugs give better engine response on Stock or lightly modded engines!
Ididium plugs, although hotter donot provide more power or response on a stock engine and ignition. In order to run Iridiums at full power, U need to get a better coil like frm MSD and or get a MSD Ignition Amplifier. THIS IS NOT RECOMMENDED cuz it doesnt give gains on stock engines.
The Bottom Line : Platinums should be used for turbocharged applications or Stock Engines while Iridiums to be used for High Power N/A Engines.