What do you guys know about exhaust systems? It seems my entire system is falling apart...rust everywhere. Still, it sounds normal. If i were to replace everything from the cat back, where can i get components and what would it cost? Can I DIY this or not? I have a lift, but I'm wondering if the fasteners would be so hard to remove that it would not be worth my time. The bolts are 11 years old, so I'm concerned about getting them off. Ideas?
Also, would an aftermarket performance system be more cost effective that the original BMW parts?