I have. Went to China at Christmas and went down there to visit. Very interesting day, a real adventure. Came back with wtc kit and they sent hull down to Aus later.
WTC now just about finished, gone together pretty well. Uses a pump to fill a bag fed thro a solenoid valve. Wtc is all cnc cut nylon, all a good fit.
They can supply a pretty nifty reversing switch that runs straight out of the receiver to operate the pump and its a 12 volt system.
My kit was a pre-production item, it was good of them to let me have it. I've made a few changes to suit myself. I replaced the supplied solenoid valve, the supplied pump just couldn't pull enough water thro it, bag filled very slow and the pump got hot. Changed the prop shaft arrangement, kit supplied with a seal and instructions not to run out of water....I put in a more conventional stern shaft.
Overall I thought it was a good kit and reasonably priced. The Chinese characters engraved into the endcaps labelling the plug holes are pretty cool too....