Cometic gaskets for the m120 will work with some modification. I know of two guys using them. I have not seen the modifications but from talking to them it does not seem major. They had to drill some holes for coolant passages. These are being used on turbo 3.4l m104 engines making around 5-600hp. I have not gotten to this point yet. I was going to see how much the stock engine could take before I go down this road. When I start building a new engine I will buy one for myself.