325ci exhaust

I have a 2002 325Ci, coupe, everything mechanically is original from the factory. I love this car but I am looking to get a new one in the next 3-4 years, so I don't want to spend a ton of money. What is a good exhaust to buy for my car that won't break the bank. I just want it to sound good, and not like a ***** lawnmower exhaust everyone hates.