Installing a GPU is easy - except if it doesn't fit in the case. I had to saw off 3cm of the upper, 5.25" bay. Just removing the bay cage entirely was not an option because I still need that for my DVD drive.

My bow saw wouldn't have enough space, and the cage is riveted. So despite terrible ergonomics, I used the metal saw of a fucking Swiss Army knife for 24cm of cut length through 1mm steel. Then I filed off the cuts so that I won't injure myself later.

However, I was too lazy to take out the mobo and shit, so I protected it professionally against potential metal dust - with a towel.