[*]Chapter 6 Stage 6-10 Traffic (This is the single hardest mission in the game{for me at least}. It sucks that I didn't noticed before getting all the other stars in the chapter) [Celestial trophy]
Stage 6-10 was way easier for me with a tech racer with speed upgrade so I didn't need to drift, except once when a boost pad would send me into a wall on a tight turn.