The stuff came today, so I finally could start putting it together.
I had some luck with the removal of the stock cooler, the 20-25 screws that $SOLID$ Necro (from Appetite4Tech.com) expected appeared to be just 14 screws. So it seems that even cards in reference design differ a bit.
Cleaning the memory chips appeared to be not that hard, the "bubble gum" thermal stuff Sapphire used left next-to-nothing on the chips after removal (99.99% or so stayed at the stock cooler). The thermal grease on the gpu was a different matter though, I was glad I bought TIM Cleaner for that. It was a sort of dark grey "goo" that came of like B-brand glue when I tried to scrape off a major part before using the cleaner.
Picture 1 shows my Radeon after the cleaning.
Picture 1. The card after the cleaning
Next step was (of course) the addition of the memory heatsinks. User reviews pointed out that the adhesive of those wasn't worth it to be called like that at all. Testing it out appeared that that was right, so I used some other thermal adhesive tape to stick them at the chips.
The applying of the heatsinks was pleasureful, because it strongly reminded me of the Lego I played with as a child.
Picture two shows the result.
Picture 2. The heatsinks applied.
After applying the thermal grease (I used OCZ Freeze Extreme), it was time to attach the cooler onto the card (picture 3).
Picture 3. The card and cooler assembled.
Once inside the case, the cooler appeared to fit better than I expected, though I messed up a bit in a cablemanagement point of view. It is not bad however, as far as I can tell (picture 4).
Picture 3. A meal of wire spaghetti.
I have really taken my time for this, so it took about five hours to do this. I am glad I took my time however, cause it works flawless. The fan speed is set at about 40% and the idle temperature dropped from 80C (core temp 85 according to GPU-Z) to below 40C. Additionally, the cooler is very silent.