I did the mod to the head gasket on my '99 SX 600 many years ago. When I did it, I asked myslef one question "If I peel the factory gasket and don't do it right will it let me down in the middle of no where?" The answer was maybe so I called Cometic gasket Co. and told them what I wanted to do. They had many suggestions on materail type and how thick the gasket should be for what I wanted to do and the type of sled I have. I ended up ordering a custom gasket that performs the way I want and I have the peace of mind that it is a new gasket made by a very reputable company. I now have about 8,000 miles on that gasket and don't ever think about it failing in the middle of nowhere. The extra cost of the new gasket along with the expert technical informatoin from Cometic made this a great purchase. By the way, I have read way too many posts here T.Y. talking about how their factory head gasket leaks or let go after it was modified by the sled owner.
Mills