Getting a new exhaust soon. I still have the old but reliable 1.8 which is currently chipped, getting a new autotech cam and will soon have dual outlet manifold and DP. What would be the appropriate sizing? keeping in mind that I have a 5th gear overdrive so highway is somewhat out of the question. Would 2" give me more torque without sacrificing hp? Or is it better to have a 2.25"?