FWIW, I have been racing VMX and vintage harescrambles over the years, and a high strung Pursang in the woods would be a handful. Clutch modulation and having the power hit at the wrong time would not be much fun. On the other hand riding in open fields or dirt roads would be a blast. If you are leaning towards the Bultaco..try to find an Alpina or Frontera. You get a headlight and a capbale enduro bike.
Here's a picture of my Alpina that I sold for $1400.
Here is the one I raced vintage hare scrambles with: