What I see in the video is that you havent connected the boost pipe to the throttle body with the intercooler between it. In the current scenario, when you connect the MAF sensor, the ecu is able to register the air that the turbos are pulling in through the MAF sensor, thus running a mixture that is required in accordance to the air being drawn into the MAF sensor. However, the boost/air that the turbos are producing is not going into the engine, thus making the engine run rich as the injectors are correctly dumping fuel as per the reading on the MAF. With the incorrect amount of air going into the engine, the mixture would automatically be rich, making the excess fuel come out as smoke.
I would recommend you to complete the loop of piping from the turbo, intercooler and the throttle body and then see how it behaves. It would be best to do this before running any further diagnostics. These MAF sensors are very sensitive in their reading so make sure that there arent any boost leaks.
