There is allot of confusion on this subject. I guess having them is a real benefit when modding these engines. I'm currently NA with simple bolt on. You read all the # 8 piston issues, and become concern with blowing your engine by modding it. I have steeda intake with Bama tune, and O/R X pipe from lethal performance, and havent had any issues. I also have the stock 3.15 gears that come with the auto. Would going to 3.73 be to much for this setup. I have very little traction with the 3.15 on take off it will spin the tires through 1st and 2nd gear to the point that the car starts to go side ways. I also installed steeda sports with tokio d-specs, and gt 500 LCA in the rear.