Removing injector seats was not an easy task. Every single one was tightly secured in its chamber.
If you are going to do this job - remember to take a break if you are getting frustrated. It will only lead to damage as posted by others with that experience.
I first tried to use the tap method (M8x1.25) on cylinder 1 to grab the washer and pull it out but that did not work. It made a nice thread and started to bite onto the steel of the head. It also started to enlarge the opening from upward pulling force. I then tried an M9 tap but it also started to enlarge the opening. I stepped away.
I soaked each seat with penetrating oil a few times over a couple hours and let it sit over night. Wanting to start with a fresh seat and thinking the penetrating oil did its job I tried the tap method again on cylinder 2. Similar results but I had more knowledge of when to stop. At this point I changed my tool selection. I had a set of Craftsman bolt extractors. The #5 fit the washer and did not bite onto the head. I stuck it into cylinder 3 and with a large ratchet it started to rotate. It took a lot of force to break it loose. Once it was able to easily rotate, I applied an upward force to slowly start "screwing" it out. I did this for cylinder 4, 5, 6 and had them out in minutes.
If I had to do this again - this would be my method.
To extract numbers 1 and 2 I tried to cut down the bolt extractor to a wider section to prevent it from biting onto the head but that did not work. I ended up finding a standard long bolt that was slightly larger than an M9. It was larger than the injector tip hole that goes into the cylinder. I screwed it into the seat and kept rotating it to "jack" up the injector seat. This worked great. It slowly made its way to the top. I feared that the steel would have damage but it did not. I think the penetrating oil and dull end of the bolt saved it. Each cylinder has a nice smooth injector seat.
I noticed the freeze plug between cylinders 1 and 2 was not square and looked much cleaner than the rest. I had a new set of these so I removed it. Large flat punch to the side and it rotated. Then vise grips to pull it out. Looks clean inside.
Before removing the oil cooler, I washed the area with soapy warm water to remove debris and grime. It came out easy.
I pulled out the power steering pump to rebuild it. Looks like someone had a leak they quickly fixed with some RTV in the past. I have the OEM kit to replace all seals.