Well, when I provided the "X-Play" segment, I just wanted to provide some info on what others are saying about Forza. When it comes to GT4 vs. Forza based on what I provided on Forza, these are going to be the storylines:
B-Spec vs. Drivatar
LAN Multiplay vs. XBOX Live Multiplay
Excessive tuning vs. excessive tuning and some extra mods
road/rally/drag vs. all real circuits (?)
Let me talk about this "Drivatar" thing. Okay. I can recall Virtua Fighter 4. No, not Evolution, but VF4. When you go training with the available characters, you can choose to use a sort of system that allows you to help learn your AI character new moves. The more moves you teach this AI counterpart, the more powerful he/she will be against the competition. I know when I tried with my boy Kage in the game, all the moves I recalled, the AI version learned my moves and can use them against any opponent. And there all sorts of situations such as counters, throws, reversals, crouching attacks, jumping attacks, side attacks, back attacks, and all that. How does this relate to Forza? Well, it seems like this "Drivatar" can actually be a way so that your driving style is recorded so that this AI racer is more like an extension of your driving talent. To me, this is what "Drivatar" sounds like. But if I'm wrong, maybe someone like Kinigitt or somebody can set me straight about this.