I really thought this was going to be simple, but alas, it was not.
Now that I had the DV solenoid out, it was time to remove the stock DV and put in the GFB DV+.
The GFB DV+ instructions were great and clear. I should have read them in entirety first as it probably could have saved some frustration on breaking apart the stock valve. In fact, even in the photos that GFB included, the stock valve was pretty broken apart.
I've attached 2 photos of the stock valve in the solenoid, one plain, and one with details of what to look for.
Given my zero experience with any of this before, it was not really clear to me where the diverter valve ends and the solenoid begins, there are some grooves in there, some seem to move, some to not move. Up to that time, I had found several DIY videos, but they didn't actually show how to remove the old valve from the solenoid - they tend to focus on removing and reinstalling the fully rebuilt solenoid back into the car.
To make matters worse, my valve was stuck!
Thankfully, I found this awesome video where the removal of the stock valve is shown live on video. It was instrumental to help me understand what comes out, and what the empty solenoid looks like once you take out the stock diverter valve. The DV disassembly starts around the 1:53 mark.
Unfortunately, I had already damaged the o-ring groove on the solenoid out of frustration by the time I stopped to breathe and look for some better DIY video, and finally found the one I just posted above.
As you can see from the photo of the remains of my old valve, due to how it was stuck (it did NOT just come out with a bit of force the way that the one in the video came out), I ended up breaking it completely into pieces to get it out.
Also note, in that infographic, where my red and green lines meet, and the entire area inside of the green line, is the part that gets completely removed and discarded. It was hard for me to tell whether only the piece that is outline in orange comes out (this is the actual valve).
Once the stock DV was out, putting in the new one was straight forward. There is a small tab on the solenoid, and also a groove that fits that tab near one of the 3 bolt holes on the GFB DV+. This ensures that the GFB DV+ can only fit one way onto the solenoid, taking out any guess work.
It fits quite snugly, and snaps in so you know it is in. I basically snapped it to the solenoid at each of the 3 bolt holes by squeezing the two pieces together. Trying to snap all 3 at once straight on does not work, it just pops off at one end and can seem like it won't fit.
Also important to note, the GFB DV+ instructions make it clear that you must handle the red/gold cylinder VERY carefully - if it falls out of your hand or out of the solenoid, even microscopic damage can render it useless. This was good to know, as there is risk of it dropping if you're not careful when reinstalling the rebuilt solenoid back on the turbo..