Turbo Super Stunt Squad

For this achievement, you need to collect the character-specific pickups (for example Whiplash pickups) for one character in three different levels. In every level there is a total of 5 pickups, which need to be picked in a single run. With the first set of pickups you unlock Starlight Pro Shell and the third set unlocks Starlight Custom Shell & this achievement.

You can find videos for all item locations by PS4Trophies. I don't take credit for the videos. Here are the vids for the first three levels:
(Pickups at 4:49 onward.)

(Pickups at 4:48 onward.)

(Pickups at 5:30 onward.)