Last year I ran the NGK 7437-8 plugs with my APR Stage 2 (v 2.4) and I never really liked them. Idle was lousy, and just always felt "not right" to me. After about 13k I changed to Brisk ER12S, and I like them much better. Upgraded to flash v 2.8 (more timing I think) and still feels great. Even if they only last 10k it's well worth it. And they're cheap.