they are like 32 a pop… alot better than the 150 each they used to be back in 2000-2001. easiest way to distinguish the coilpack failure is the subaru like mis-fire and the flashing CEL usually helps too… if you dont have a VAG-COM or generic scan tool, the easiest way to diagnose which one it is, is to have the car running and unplug one at a time until you find which one doesnt disrupt the already terrible idle.