Bosch +4's are one of the worst ever designs for spark plugs.

one: electricity takes the path of least resistance, therefore, it will only spark from the center electrode to one of the four outer electrodes at any one time. in other words, it'll be no more powerful than a stock platinum plug.

two: 4 side electrodes further shroud the center electrode more than a single side electrode. this keeps the spark away from the conbustible mixture, causing stumbling, poor throttle response, reduced fuel economy, and higher emissions.

three: platinum is a horrible conductor compared to copper/nickel or iridium.

four: you'll "feel" an improvement with ANY plug, normally because your car was in need of a tune up anyways and already lacking power due to this.

five: all plugs must be properly gapped and have the proper insulator sizing to prevent detonation and/or misfiring. only the Bosch +4's cannot be gapped due to it's design.