The price pales in comparison to the expense you will have if BATFE thinks your rifle should not do that and you hire an attorney to try to keep you out of jail. I suggest you entirely avoid anything that resembles remotely a violation of Class 3 laws or live in a state where you can legally own Class 3 and pay the tax stamp.
I don't think the GSG has enough recoil for that sort of operation.
They work as advertised and come with a letter of ATF compliance...that is until the ATF changes their mind. They will work on .22s as well and there are vieos of it running on a S&W .22 AR but the way they work on the AR prevents it working on anything else. I do hear they are working on an AK version though.
The ATF has changed its position on several products in the past, leaving the owners without their stuff and out their money. Not risking my dough.
