hey dude i was reading your note; dont know much about yamies, i work with kawies and mercury outboards. when i rebulid i always use wisceso i think that they are worth the money, on the other hand i have never paid full tilt for them either. wiseco pistons are forged (made out of one piece of alum) not cast (poured into a mold.) out of the box weighed with no rings they are within grams of each other and are probly the lightest pistons from the factory. some people say the burn up fast; only time that has happened to me is when i advance the timimg too much; i think wiseco is the best on the market, i have a hot rod crank from wiseco also its been great too. if you get me some part numbers for pistons i might be able to get them a little cheeper for you. only thing is shipping your on the west i'm on east; but if it saves ching ching it might be worth it to you let me know