Not had an hour on game yet but I'm wondering about the A spec and B spec do I have to have a Bspec
Unlike GT4 B-spec is actually part of the game in GT5. I don't think you can get to 100% without them. Plus they will get you some cool cars in their races that you won't get using just A-spec.
you dont HAVE to so Bspec, but like he said, you can get good prize cars for doing it.