I have decided to turbo my m20. And I have decided to use e rods and I pistons, I have heeard that this combo will lower my CR to about 7.5:1, But I am stuck on how thick my Head gasket should be. Should I keep the stock thickness or if I get a .120 or .140 thickness will this drop my CR lower? I wouldn't want to go lower than 7.5:1, I appreciate all advice in advance, thanx.