I just had a new catback exhaust system built for my 99 yesterday. I went 3 inch with a Magnaflow muffler. Wow it made a big difference in performance it is a bit loud for some but we really like it. My stock system was necked down at the end of the header so we cut it off there and went 3 inch all the way back. My muffler guy said he had never seen one like it and he had done a bunch of them. Anyway we are very happy with the results.