I've got Bosch Platinum +4 Spark plugs in my car right now but need to change them. So which is better Bosch Platinum +4 or AC Delco Rapidfire. I've hade people tell me that they notice a power difference when they install the +4's but I hadent driven my car much befor swaping to them So I have no idea if it made any difference. But they seem to be good plugs. But is the Rapidfires a better plug.