Vape Carts

IST furnished me with a Sour Diesel Xtractology cart, which is a thing of wonder - very strong and really discreet for public toking. He is out of stock though. I don't really trust Fat Freddy's Cat and thcfarmer2 looks like he's slung it together, so I don't want to take the punt. I want the real deal commercial vape carts. Any thoughts? EDIT: UK>UK only! The cart is for health reasons, so I need something legal (at least somewhere).