I found a guy that is going to sell me a 512mb stick of RAM for $15 shipped. That should get the build that I am working on for my folks where it needs to be.
Honestly I don't really know a whole lot about snort. When I had my IPCop box I just turned it on, and subscribed to the Sourcefire VRT rules.
This is the first that I have heard of ac-bnfa mode, but it sounds cool. I'll check it out
I'm not even sure if I need snort for my home network. I never realized that it was such a resource drain. Added protection is nice, but my main concern is speed.