I have done the tune port swap twice. I love it for reliability. I am running stock engines though. If you are doing different cams and bigger engines you need to use the mass air flow system. It can be tuned to bigger engines. The speed density systems are not very good with major modifications like you are talking about. Try the site thirdgen.org or thirdgeneration.org . There is a lot of real good info there about tune port motors and modifying them
