I agree 100% with you as well, kcheeb.
alleycat,
You raced with us the entire night and not once did I feel like you were slowing anyone down. Your pace was good and you drove clean. I'm not sure what else I could ask for from a league member (other than a mic lol). But in all seriousness, I would take it as a personal defeat if you felt that you weren't good enough to race with us. Please look at the title of this thread. After the name of our league, the first words are "beginner-friendly". That means even n00bs are welcome as long as they drive clean, and you are definitely much better than a n00b.
Furthermore, as kcheeb mentioned, you will never get better at racing humans (or cyborgs like diabolic) if you don't actually spend time doing it. Racing against AI will never improve your racing skills against human competition. There isn't any AI in the world that is good enough to do that, and GT5's AI is far from the best anyways.