Don't forget to check out PixPlant and CrazyBump.

Personally, PixPlant is better value as it does the seamless textures. I trialed ShaderMap and found it a bit of a memory hog.

i will recommend pixplant.

Not necessarily darker as the projection light source is independent of the exterior sunlight.

When in doubt, I will google for an example and if that produces nothing I will do a small quick-and-dirty mockup to study the effect I am trying to reproduce.

Of course, you can also build the projection effect right into your model and not have to do anything in post. However if you understand what the result will be it can be quicker to fake it.