So what would be the best way to take the downpipe off an 04 SS? Going to be replacing the cat and just want to know

 

I would use a socket or a wrench .
I would use bp blaster on the bolts

 

I would spray it down with PB blaster penetrating oil several times before attempting to break it loose. I would use a 6 point socket or wrench because they grab better. Heating it up with a torch will work too if that is an option.

 

If you have enough room, use a socket. Otherwise you'll need a wrench. Mine are 15mm bolts.

 

I got to all the bolts from under the car. I was lucky the ones on the rear manifold broke free (I had to use a monster long extension on my ratchet to get them, but it worked).

 

What would be the best way to get it off the front part of it? I already got the back off near the resonator, but I can't figure out how to get the front off

 

I repeat, I did mine all from under the car. When you say front part, I assume you are talking where the downpipe and rear exhaust manifold meet...

I had front of my car as high as I could, the rear wheels blocked. A ratchet and some long extensions to reach the nuts/bolts holding them together. A little hit with some PB Blaster prior to and during the job and all came apart perfectly. I did zero work for the downpipe from up top.

I'm sure others have done this job differently.

 

I sprayed mine with PB Blaster and let them soak. Then I put the car up on ramps and slid under it. Using a long extension, I was able to break the bolts free from the manifold/downpipe very easily. It was super easy to do.

 

Thanks for the help guys! Greatly appreciated!