Kronik Racing near me in Simi Valley, California have been selling zs190 engines and whatever install doohickey is needed to install them on Boom! Vaders. He (either the owner or one of the owners) seems on and off on shipping bikes (mail order), but doesn't mind shipping them to Las Vegas, and they do have a Craigslist presence on the LV Craigslist. He might be more willing to ship the zs190 engines nationwide, but the last time I spoke with him a few weeks ago, they were waiting for a shipment of the engines to come in, and were soon to sell out their last batch of Vaders. I suggest to call them since I know they have been in business for several years now (meaning they are reliable) and have taken the Vaders under their wing (meaning they have sorted them out). Since they were originally a pit bike and scooter dealer and pit bike racing shop, they know their stuff. I did tell him to join here, but not sure he understood Chinarider's presence in the Chinese bike world.
http://www.kronikracing.com/