Good review. A few points that I'll make that you talked about....
Mine has the Gen 1 guide rod (if you want to call it that) and it looks exactly like the silver aluminum one pictured above, except mine is black steel. It has a rubber washer and a metal smaller washer on top of that (I'll take a pic of it some day) and I've never had any issues with it. I guess the X or H style guide rods are the problem childs.
When you change grips and if you want to use the better looking grip screws (torx or allen head), you'll need to change the bushings out since the existing ones are too big. Since the frame threading isn't that great, you might need to use a tap to clean up the threads before putting in new grip screw bushings.
I removed the ambi thumb safety and use a Colt non-ambi extended thumb safety (this one for $15
) and it dropped right in without any mods needed. The shape and feel is exactly like the factory GSG ambi thumb safety, but it feels more solid when engaging & disengaging the safety now on my gun.
I noticed on my GSG (along with others I've read about) that they initially shoot high right at distances of 15 yards out and further. After adjusting the sights, and getting a better barrel bushing (the stock GSG one is pretty loose), you can get some really tight patterns at 15-20 yards easily.
Sounds like your GSG ate up the Federal blue boxes pretty well.... good to hear. Now go out and shoot it some more