Airsoftjunkiez, perhaps the only airsoft store that is highly specialied in HPA-powered airsoft products are stockists of various HPA engines from different HPA airsoft manufacturers. This includes Wolverine Airsoft and in this video they show the Gen 2 Storm Regulator, Quake, and Reaper engines. You can get the Quake and Reaper Combo for US$515 at their online store.