Exhaust System: Buy Online Now!

Hello,
Okay, here's a question. I often read things here like 'replacement exhaust pipe,' and then some people say the engine will break because there's no back pressure, while others say it won't break because back pressure doesn't matter, etc., etc. Then I hear that with diesels, you can't get a different sound because the exhaust pressure is too low, and somehow, it seems like nobody really knows anything. It's worse than a ladies' coffee klatch!

Okay, over to the experts:
It would be really great if you could write an article about it to clear things up.
How does an exhaust system work? How does it affect turbo performance or engine power? What is the purpose of back pressure, etc.?

I really don't plan on installing an exhaust pipe like that on my car (I don't think a diesel engine sounds sporty), but I'm interested in it, and I'm sure many others are too.
It would be really great if someone here knows about this.

P.S.: It's been a while since I was here, and it's really gotten much better.