Too many achievements at the same time if everything that is hinted is true, for sure... but y I highly doubt it. Seems almost impossible. Let´s recap:
- Day/night transitions -> Ok, but only in some circuits and with some compromises in lighting for sure...
- Dynamic lighting -> Really complex isn´t? Ok, we have one light source (the sun), but if the light is dynamic, and we have races at night, what happens with lights from cars? Are they going to simulate that too? Generating shadows and all the stuff? Seems like imposible, but... I bet for some specially designed tracks with the assets restricted in order to reduce graphical load... If that´s no the case... they´re doing arcane magic (60 frames/high resolution at the same time)
- Dynamic weather -> That´s simply beyond belief, even in "special" tracks and situations. Maybe if Top Gear track is the only that implements that feature, with "custom" test conditions, only one or two cars and so on... could be very interesting in order to play with physics and driving model. But Madrid in a rainy day? Impossible I think.
- Track generator - track or just paths in Top Gear track with cones, tires and the same stuff? If there´s a track generator, I bet for a simple one, with very basics assets, but at the same time that could be a killer feature, because driving is just... driving, a car with the adequate track layout, elevation, etc can be really interesting to play with, even if the assets are somewhat "poor" and generic.
- Go carts - Why not.
- 40 tracks with 100 layouts - That would be simply awesome. 20 seems more "doable".
The features in photo mode don´t excite me as much as all the above.
Let´s be serious, if they manage to do all that, even if the implementation is far from perfect (what I doubt considering the somewhat "extreme" Yamauchi´s behaviour, he´ll drop the feature if the quality is not enough), the game is mindblowing content-wise. Just the definitive car game for a long time. Too many improvements at once. But I don´t know how it can be done with a five years old hardware, 512 MB and so on, and the high quality stuff that we have seen already.
GDC it´s going to be very interesting.