From Shin'en Twitter page:
The following come from Shin'en's Twitter account...
(About the 4K-8K textures) Yeah, streets took a lot of resolution. Tho biggest textures are used for the shadows.
60fps (with minimal dips here and there that we try to iron out)
Smoke and mirrors all over the place, otherwise we would be at 20fps.
No, we use realtime soft shadows. So we can have dynamic weather and the games size is much smaller.
(TOD feature) It's realtime. As a race is just a few minutes there are not much visible changes, beside some clouds moving.
SSAO is by definition dynamic, tho it's (almost) impossible to get working in 60fps ;) Technically: Every console is outdated