iridiums actually have a longer life than coppers.

there are many schools of thought on it:

-coppers are cheaper, nascar and top fuel run them, blah blah blah. top fuel and nascar also run ignition systems that are alot more powerful than stock, amp wise. coppers are great conductors, but this also means they attract all the residue and whatnot, and foul faster....this is why every 2-3 oil changes, you need new ones (but it works since they are cheap).

-people say not to run platinums in boosted cars. there's really no problem with this, but theyre mostly just the middle ground. coppers are cheaper, and iridiums fire better for the price.

-iridiums dont require as small a gap as coppers to get the same spark, and last alot longer. the copper vs iridium arguement is null since changing coppers out every so many times @ a cheap price is just about equivalent to changing more expensive iridiums out once in a great while. iridiums have worked well in many KA/SR boosted applications.

basically find your heat range that suits you, and start with a good quality gap. the more gap you have the more spark there is, better burn, etc etc. you want to run the largest gap you can without having it blown out (misfiring).

try some bkr7eix plugs at .030". if you're running over 14-15psi, you'll likely need to use a .028" gap, or run a .025" gap to be safe and not have to worry about gapping down later.