I'm surprised you like that "snake shaped pipe". It has only a couple of inches of header pipe, and the expansion chamber is very short.
It looks like you already have a great pipe, you just need to add a muffler and some exhaust wrap (and a nice big air filter and box for your intake?)
I just ordered a Honda CT70 exhaust from ebay. I wanted it for the header, which is 25mm OD so possibly 22mm ID. It has a couple of bends, nearly 180° and about 80° so I am sure I can make something work. It needs a flange welding on, of course; and actually I may reverse the header to get the pipe fitting the way I want it- under the downtube.
CT70:
View attachment 81305
I'm presuming the rear section is a muffler, not an expansion chamber, so I'll be using the header with either the Aprilia RS50 expansion chamber, or I'll save that for the next build and use the CT70 header with a homemade expansion chamber.
RS50:
View attachment 81306
I quite like the look of the Sachs one that's on eBay right now, if indeed it is an expansion chamber and not a muffler in the shape of an expansion chamber, lol! (You'll have to check with the seller)
Sachs:
View attachment 81307
Search eBay for SACHS MOPED SCOOTER/MOTORIZED BIKE EXHAUST PIPE for more pictures of it.