There are photos of the ProWin AR9 kit for the Marui MWS rifle. This allows the use of GBB 9mm Glock style magazines and photos of it can be seen on both Airsoft Tiger111hk pages and also at 波子兵團 Prozi Shop.
The new kit if out on the 7th of April and looks like a well made piece of kit, although there’s no word on unit price at the moment.