Most components added to a plane forward of the center of lift usually have a negative effect on directional stability (other than canards perhaps)....
Recently, I worked with a friend from San Diego after he purchased a GlaStar that had briefly flown. He wanted the GlaStar to undergo a complete make-over plus some upgrades.
Break-in of an engine refers primarily to the initial phase of operation in which the piston rings will "seat" against the cylinder walls.
Run-in refers...