When buying a rebuilt power head is that going to come with all new pistons and rings, crank and bearings and seals. Or do they just take a core like mine and fix what needs to be fixed? Another words is a guy going to end up with a like new from the factory power head. <br />Or would it be cheaper to have a machine shop go thru my power head and do the just fix what needs to be fixed. I guess what I'm trying to ask is what is the pros and cons. And would there be alot of difference in cost by going either way.