It might work but here is the major problem:
The fitting on the cylinder on a PA50 is a spigot fitting, not a flange. By this I mean that the PA50 pipe fits up into the cylinder to make the seal. The pipe shown has an oval 2 bolt flange. To make it work you would have to get a stock PA50 muffler, cut the header off of it as well as cutting the header off the proposed pipe and weld them together such that the pipe will mount up ok and still allow the use of the centerstand.
Also, most of the pipes made for the Chinese mini bikes are for an engine that runs in the 12,000-14,000 rpm range which is way higher than a Hobbit will do.
You are better off getting one of the Leo Vince pipes that are made for the hobbit.