I track my car, you can see my thread in modifiers-pocono raceway. I have 3 inch exhaust and with all of the suspension mods in the rear there isn’t much wiggle room for the tail pipes. If I have to make suspension adjustments I usually burn myself on the tail pipe. My car is lower than usual also. That is why I asked for muffler type also. I can possibly modify my current muffler to tuck up under the car better. Then I was thinking of a 1 1/2 inch x 6-8 inch rectangular exit at the pinch weld