As the (probably) first user of this installer, i would prefer only LiteEditor. My point of view is that most of the plugin devs probably have there own MinGW / wxWidgets installed.
What do you think ?
edit : I missed the point

I just have to create a new iss file containing only SDK. This way, those who want to create plugin can use this installer to install SDK only, and install it where they want. This is the good solution IMHO.