Hey there,
I second the machine, the vaporizer you linked looks good for changa, whereas the machine is good for crystals.
I would go with something cheap (or free) to start with, and then decide if you want to lay out the dough for a new vape.
You may be able to use the machine so efficiently that you don't need anything else, and changa/enhanced leaf can be smoked in anything with great results. Vaporizers may be hard to clean or get oil on the internal components if they are not designed for extracts and oils, so keep that in mind.
If you do get a vape, let us know how it works for you, more people are trying out different units these days and it would be great to know which ones work well and which ones are not ideal for spice.
Also what do you mean when you say you "I'm not sure I want to use a flamethrower too often in public"?
I hope you're not blasting off at the bus stop or something.
Good luck, let us know if it works!
AcidShard