My brothers car has a 3" TTI X-pipe exhaust feeding Borla Race mufflers and 2 1/2" tailpipes over the axles to factory appearing tips. I have been itchin to remove the exhaust to see if it benefits at all. I will be monitoring the wide band oxygen sensor and make the necessary adjustments so the air/fuel ratios are the same for comparison. It would be nice to know if the car didnt benefit from open exhaust because its a real pain in the booty to take the exhaust off at the track.