I was reading through this thread as I am getting ready to upgrade my head since I am going to do dual cooling at the same time. My first thought was a Blowsion head but after researching it I have found that theirs as well as the ADA are interchangeable domes. I have had heads like this on my two stoke 250R atv and found that they are nothing but a hassle. Mine always leaked through the o rings around the spark plug hole and ran down the side of the cylinder. Even when they where sealed right they would only last a few months before I would have issues. After having a highly modified quad I am trying to find the happy medium with the ski between adding power and compromising reliability. This being said I would like an honest opinion and on the interchangeable domes as far as the leaking is concerned. I don't want to deal with that again so I was thinking more along the lines of the Cold Fusion head. Though after checking it out I see it is still a two piece design. The guy there also said that with the interchangeable domes you have problems with uneven cooling on the cylinder. Any thoughts are appreciated.