I purchased one of those DIY Spray Foam Kits to insulate the rim joists and air space at the top of the rigid styrofoam insulation in my quest to finish off my basement. Thought I'd share my experience with the Fine Homebuilding community. Overall the kit worked as I expected. The blog post below has a link to some pictures of the kit and video I shot of the process.
I decided on this closed cell kit after a lot of research on the web and viewing videos on YouTube. I'd be happy to answer any questions from someone who's contemplating doing this.