I agree with this method. Between going through the inner fender area and through the top, you can get to everything you need to. I also removed my cats to allow more room for the headers to get in & out. Also, it is usually easier to either cut up or bend flat, the heat shields to get them out.I didn't unbolt the motor from the mounts. I put the front frame on jackstands, and took my front tires off. Then I took out the inner fenders and worked through there.
I had to bend the heat shields up pretty bad but they came out. The bolts that hold the heat shield broke off in my manifolds.
I also took the o2 sensors out and dropped the cats for more room.
It was quite a project, mostly because I did it alone, but it wasn't that bad.