How to find an exhaust leak:You may have to put your car up on stands to do this, if you can't crawl underneath it when it's on the ground. Have a friend get a news paper, or note book, or something. I use a few pages from a news paper. You're going to use the news paper to cover the tip of your exhaust. This will start to get hot, hence the news paper! Fold the news paper a few times until you have a thick square of news paper large enough to cover your exhaust tip. Now you have your news paper folded properly and your friend. Start your car and let it idle. Now have your friend cover the exhaust tip with the news paper and press HARD. His job is to create as much pressure in the exhaust system as he can, he'll build up high pressure quickly, but tell him to keep pressing.While he's pressing against the exhaust forcing the gas pressure to build up it's time for you to crawl underneath the car. You'll be looking at the exhaust system. Feeling with your hands for exhaust spraying out of some hole or flange (Don't touch the exhaust pipe, it will burn you). You also need to be listening. The leak will make a hissing noise, that should help you hone in on the leak. Another thing to look for would be a small black whole, or blackness around one of the flanges.With this simple and cheap method you should be able to find your leak.As for areas prone to leaking, I would check your flex pipe. It's the part of your exhaust that's made out of metal mesh.