Replaced the hydroboost in my '04 Sierra 3500

Pretty straightforward job, just wanted to post some observations about doing the job myself:

The retaining clip on the brake pedal faced downwards, so I used a stub screwdriver to pry the center part out, then pushed the clip up. You may need to push/pull the clip (depending on which way it's installed) so the center part can be pryed out, as it has a lip that will catch on the bolt threads, preventing it from moving.

I used both a 15mm regular and deep sockets, for the inside bolts on the 2 nuts nearest the steering column, the deep ones getting them initially loose and to tighten them at the end, but the regular one to get the nuts off/on, as the clearance around them wasn't enough for both the deep socket and the wobble/u-joint. I also found putting the nut in the regular socket, then working the socket with my hand worked well for getting the nuts started when installing them (vs trying to get the nut started by hand without anything else). I used both kinds of wobbles, I prefer using the impact one as it doesn't flop around as much, but I needed the regular one for the top one by the steering column as the angle was just too much for the impact one.

For taking off the master cylinder from the hydroboost, using a impact on the nuts may spin the studs instead (they are actually bolts screwed into the hydroboost. Putting a wrench on them while doing it prevents that from happening.
For doing the swap, I removed the lines and immediately installed them on the replacement HB to minimize the mess and getting crap in the fittings. The lines are long enough so that the replacement HB can be next to the alternator while doing this. Just make sure the lines go the same way w.r.t. each other and it's no problem. I also put a large rag in the engine bay underneath the HB's while doing this to further minimize the mess.
The only real problem I had was the final step of reinstalling the brake rod/brake switch to the brake pedal lever. I spent 15 minutes getting frustrated trying to get it together, before looking at several youtube videos on the process and realized I was trying to get the switch on the wrong way. Flipped it around and it went on no problem. I found it helpful to remove the cover to the fuse panel at the end of the dash, and look through it to see the pedal/switch/rod from the side to get it all aligned right, and then install the retaining clip.