Laguna Seca - Looks exactly like GT4. Needs a major overhaul.
Cote d' Azur - Looks good and fun to drive. Buildings need more detail and less barriers where they're not supposed to be.
Tsukuba Circuit - Looks good texture wise, just needs more touch up in the polygon count.
Grand Valley - Looks good, but seriously needs texture updates, especially the water texture under the bridge.
Trial Mountain - Looks exactly like GT4. Needs a serious overhaul.
Autumn Ring - Looks good, for now. Needs an update later.
Deep Forest Raceway - Looks exactly like GT4. Needs an overhaul.
Suzuka looks good for me for right now, but it may need to be re-evaluated at some point, though.
So basically, these are the "standard" tracks in the game and need to be converted to premium, especially the first three. Time and weather changes should be applicable on all tracks that apply.