xfag SPACE emperor
As far as the physics model, what I am planning on doing to test them is to pick the same car with the same tuning settings and do a few laps on Suzuka....but that would require Sony to A) release the game here and B) add tuning to GT5P. I can't guarantee GT5P's default tune is the same in Forza's.
Again, PD has said very little about the game's actual driving mechanics...but they have no interface with the community like T10 did, so I guess that's not altogether (lol like the andrews dude lolol) surprising.
I was pretty impressed with the Professional setting in Prologue Demo, but it's such a small taste that you can't really say anything conclusively.