Installed Bosch +4s back when they came out years ago and added a set of Magnacore wires. Never gave me trouble. Wife's Tour went through OEM wires one by one. I installed a set of regular Bosch wires and the problems went away. I changed plugs on both cars mainly because I wanted to remove them while they can still be removed. After awhile they sieze to the head. They may last 100,000 miles under the right conditions but I wanted better performance and a coating of anti-sieze on the threads.
