Has anyone tryed this combination? just wondered if it was possible, stripped engine last week and found one of cylinders has a chip off one of the ports(think they call it the boost port at the rear), and also a crack in the bridge between exhaust ports,nice!.Not sure if it's worth getting them repaired and re-plated when i could spend money on a secondhand set of 18's or maybe if i can 21's and have more power.