If it were me, I would go to Rocket Motorsports and get these Spark Plugs, he modifys them and they make more power on a dyno than Iridium ones.
http://www.m24x.com/products.htm#

Just click on the RM Modified Spark Plugs, also get some REALLY good spark plug wires. How much HP will you be runing, what kind of tuning are you going to have on this car, have you changed any internals at all?