I'm replacing my exhaust on my 88 740 GLE (B230F, n/a). I got the parts from FCP. Here's what I bought: manifold gaskets, header pipe, catalytic converter, center muffler, seals, clamps, universal O2 sensor, and motor mounts which I will worry about later. BTW, all parts totaled about $430 including shipping. The axle pipe, rear muffler and tailpipe were replaced recently and are in good condition.

Not sure about the manifold, but I thought I would get gaskets in case I need them.

I have a few specific questions; and any other advice would be great.

1. Should I try to pull the manifold, replace the gaskets and retorque it with new studs and nuts? If so, I am very worried about getting the old studs out.

2. I am quite certain the O2 sensor and cat are bad. Did I ruin my shiny new rear muffler by driving 3000 miles with the components upstream being bad?

3. What size O2 socket do I need? Can I rent it from AutoZone? Any tricks to hooking up the universal sensor? (yes, I'm too cheap to buy a Bosch)

4. Is this project going to ruin Christmas for my wife?

Please feel free to interject any and all opinions!

Happy Festivus, Gre