If you want a cheap plug that last under 10K, then for your mod level, the one step colder than stock AL 605's are a good choice. If you want a good plug that last a long time then the NGK Iridium TR55IX would be a good option, although pricey compared to the Autolites.
Iridiums come stock in the newer models and are fine. I've noticed no difference running any of the copper or iridium plugs, KR or otherwise. By far the best plug I've run is the Nology (Brisk) Silver Racing, but they are VERY pricey.
