PhreakdOut wrote:^^ This really is not that hard. Just take a breath and read the postings carefully.
> The nuts should be removed, not the studs. The studs are welded to the OE muffler.
> If it have not been replaced before, the OE is low 409 grade stainless steel. 409 will get rust on it and make it difficult to remove but not impossible.
1) Use a wire brush or something similar to clean off surface rust from the threads of the stud and around the inside edge of the nut.
2) Use some type of penetration lube spray. PB Blaster is good. Just use anything available.
3) Use a 6 point deep socket to remove the nuts. A breaker bar is best or use a socket wrench and add a pipe or some kind of extension to the handle to give you more leverage.
4) Turn carefully! Nice and slow. If it will not budge with mild force, then apply heat.
5) Propane torches are cheap. Any hardware store will carry a kit for about $25-$35 dollars. Heat the nut evenly all the way around. Work with one nut at a time. Do not try to heat the stud too. You want the metal of the nut to expand so it is easier to remove.
6) While the nut is hot, quickly use the wrench to remove.
7) If it still will not budge, then look into a nut splitter. AutoZone may have one for rent. Check with them. It looks like this:

Basicly a tool steel point is driven into the side of the nut until it splits open. Hopefully you have clearance to fit this onto the flange.
8 ) Worst case scenario: If the mid pipe looks bad too, replace it. Cut the OE system in two with a wheel blade pipe cutter. You can use an aftermarket mid pipe, have a shop make one for you or get the OE midpipe.
Please post up pictures if you still have problems.