Deng is the creator and owner of some trials brands. As Dale-hill explain some in his post. Some people just don't like/trust his products. Just don't buy a deng made free hub. Anything else is fine I think.
The only thing that you may want to think about is the chain line? I take it you have a cassette/free hub? If so then it should be fine to put a couple of sprockets on there with the tensioner. Correct me if I'm wrong.
Just let people remember, this is jack c. The kid who somehow got into full members but should be in new members? Can a mod/admin please send him back?
Lesson!!! 0:52 can see the lesson logo on the downtube in pink. And a few other parts through the video. And big clue, his t-shirt at the end says lesson.