I don't think there's a dedicated GSG1911-22 thread, but they pop up a lot in the 1911 and rimfire threads. It fits a lot of 1911 parts, supposedly 80% interchangeability, but I haven't played that much.
For me, I swapped out the grips and the mainspring housing (to a flat one) and that's about it. Surprisingly, standard 1911 grip screws don't thread into the GSG 1911 frame....different thread pattern?
Anyway, it's cheap to shoot, accuracy can depend on the type of ammo you're using. It's fun to do mag dumps with it because you can get stupid without breaking the bank.
Here's mine, its an older pic still with the orginal MSH.
http://1.bp.########.com/-PnZES3MrwLM/UfTz4ba97PI/AAAAAAAAR5g/t9N0xKYC-9E/s1600/P7261699.JPG
It's actually not that surprising, what is surprising to me is the number of parts that actually will swap over to American 1911 .45's (GSG's and the Sig variant are German {read European=metric}) The thread pitches are metric but the pins all swap back and forth NP!



















































