Has anyone tried the big bore kits offered for the Dolmar 6400-7900 & Makita 6401-7900? They advertise 85CCand the cost is only about $148 including the cost of tools and gaskets. I saw a video of one on you tube and it was really ripping through wood. I would love to try the kit out if I could get a used Home Depot rental 6401 on sale for $200-225. I did hea the kit is made in China so I wonder about reliability and how much damage it would do to the saw if the piston blew apart. I have a stock 7900 that I could run against to get a good idea of how they compare. I will not mod the 7900, it is too new to risk blowing apart.