Awesome game, the one I enjoyed the most on my phones!
Of course I have all gold medals.
Track records are (all with the bonus car, Good Oldie):
Grassy plains 50.2
Sandstorm speed 1:18.1
Night race 1:12.9
Morning frost 1:27.7
Blizzard passage 1:12.5
Dark hill 59.0
Dirt road 1:05.6 - the hardest track without doubt
Northern summer 51.8
Frosty forest 1:19.2
Sand cliff 1:22.3
Green mountain 1:41.2.
Of course they are to be improved, but I don't take this game that seriously.