I just got back from NSXPO in Atlanta. I was initially worried that I wouldn't be able to keep up to the cars that had been upgraded since my car is basically stock. A lot of the cars there seemed heavily modified. However, I noticed a curious thing on 3 of the 5 rides I took. In these 3 cases, the car in front of me had an exceptionally loud muffler. I assumed this would be associated with a significant power increase and I would struggle to keep up, but the opposite appeared to be the case. These guys stomped on it and made a lot of noise but accelerated very slowly. In several cases, their slow acceleration during passing actually seemed unsafe to me. I was able to keep up without even downshifting and practically ran into the back of them when I downshifted to maximise acceleration, because I had anticipated they would step on it. It seems folks are slapping on loud exhausts for some sort of safety benefit of everyone hearing them without considering the lost horsepower of these ill-tuned units? After the 1st occurance I had assumed that the driver was still learning to shift a manual transmission, but after the 3rd different car like this I am perplexed.