The Mini Powercore 4 is the best bang for your buck performance bolt on for your mini. Offered as a standard Mini Powercore 4, Closed Course Big Bore System or as a Spark Arrestor Version, the Mini Powercore 4 features a Hi-Flo stainless steel core and formed end caps, an aircraft grade aluminum canister and a durable stainless steel header. Its pounds lighter than stock and you will swear the motor has been bored and stroked with the first twist of the throttle.