Joe Danger

A time star is achieved by hitting all targets and finishing the race without running out of time. If you miss a target and forget to collect them all, but finish the race in time, then the star won't unlock and neither will the trophy.

The easiest way to get this is on 'Second Tour: Comeback Tour, First Event: Mostly Dangerous'. There are 5 targets to hit and the time to do it in is 33.0 seconds. This is easily achievable and you should get it on your first playthrough. You don't need to collect all of the mini-stars or hidden star to get this trophy.