I know bugger all about this, but can anyone let me know anything about sports exhausts on a vs commodore. I can apparently get one pretty cheap, the bloke i was talking to dropped words like 2.5" and extractors. I know what these are, but not much about how they affect the car. Will it just make the car sound better or wil it effect performance of your car, and fuel economy, and things like that. If you have any info on sports exhausts, please let me know.