As has been said by others, having a comparable plane to your local competition is the best choice. Here in New England we fly stock and open classes. Stock is a plain bearing (bushing) .25. Going with Norvel .25s makes them competitive in open class as well. The lighter plane out turns the larger engines. Speed is for running away! I also like my OS .32ABC with an 11x4 prop. Pure vertical but turns nice and tight and doesn't slow down in manuevers (but illegal for our local "stock" class) The whole reason we standardized on OS .25FPs originally was to level the playing field and have it be skills rather than wallet.