I have owned my car for a few months now...I sent it to fox valley and they went over it and said the noise was due to a bad turbo and it needs rebuilt. I told them to do both since the car is almost 12 yrs old with 34k miles. The noise is inconsistent and only at idle. The car is wicked fast so i do not think any internal problems. The car also has 200 cell cats and no mufler...so i sided with them because it made since that it was stalling out and the back pressure was making it spin again. I said as long as it fixes the noise i am happy...3k of turbo repair and still have the noise. They now say there is no back pressure because of having no muffler. I would believe this if it did it out of both sides. anyways i am looking at getting a stage 2 chip from p.u.k. and one of the reviews on the chip says it fixed his lean pop on trailing exhaust. I dont know if he means what i have or when you let off the throttle. I am thinking of buying a stock exhaust to see if that fixes it. Has anyone had this problem and if so was it do to the aftermarket exhaust ?