I have CMI`s on my Top Gun and I am very happy with them, also have several friends with CMI`s and they are also pleased with thier product also.

I have owned several sets of Gils and have to say that I will never own them again. I have had problems with them and lost a motor once because of an internal leak. They are coated internally and externally with what they call "Gilcoat" It looks to me like some type of powdercoat process. After a season or so this stuff flakes off and looks horrible and in the waterjacket it peels off and clogs the water flow big time. I guess they were fine in thier day but with the price of CMI`s now about the same as Gils why would you want them.

Just my personal experience

Klaw, A very reliable and very well known engine builder here on Long Island helped me make up my mind. He has seen the problem with CMI's cracking within a short period of time. CMI's warranty comes back with a "sorry, salt water thing" and your S.O.Luck. The only time he uses CMI is for higher H.P. engines. I was really disappointed because I was looking foward to using CMI's but really can't afford the big bucks every couple of years. The gil's I have are 10 years old and am in the process of shipping the entire system for a pressure test at gil's plant just as a precaution.

KLAW
The CMI's are a real nice product, they look nice and give you some additional hp, but they do seem to crack after two or three seasons.
The cracks seem of show up in the exhaust pipe, and not the maniflold. I'm convinced they crack from movement, combined with expansion and contraction.
Talk to CMI I have heard they have made some changes to the geometry where the pipe meets the exhaust manifold.
The ones that I have worked on have a tapered clamp and a fiberglass rope gasket , I do not know the technical term for the connection.
Good Luck Post what you decide to do.
Brian