Jammes Downs, please shut up. Race gas can be used in ANY situation where pump gas does not provide sufficient octane to prevent detonation.
Boosted cars use race gas all the time. Some because they need it, and some for insurance. A hole burned into a piston sucks a dick.
Oh, and Rogue Male, in the end it's CFM, not PSI that matters in a turbo application. People use large® turbos to move a larger volume of air.
OH! BTW, put stock temperature range plugs back in your car. You're not running boost. You're not sprayed, and you're not running an 11:1 compression ratio. (unless you're hiding something) The Iridium plugs do not reduce detonation in your case, because (barring mechanical/electrical failures) you simply don't create the conditions in your combustion chamber that would lead to detonation. The ONLY reasons you would have detonation are: You got a tank of shitty gas, you have a fucked up water passage somewhere in your motor and a cylinder is getting insufficient cooling, you fucked up your MAF when you installed your 4" iceman Xtreme intake, you have a clog in your fuel line/regulator/rail/injector, you reinstalled your plug wires backwards. I'm tempted to lean towards either the bad gas, or there is oil on the MAF sensor from a K&N style filter.