Full list of all 38 GRID achievements worth 1,315 gamerscore. It takes around 200-300 hours to unlock all of the achievements in the base game on Xbox One.
The base game contains 29 achievements worth 1,000 Gamerscore, and there are 3 DLC packs containing 9 achievements worth 315 Gamerscore.
Drove a total distance equal to the circumference of the Earth
You won a race in a Ravenwest livery with Nathan McKane as your team mate
Won a race by crossing the line backwards
Purchased at least one car in each class
Won an Event with at least 3 other racers using a loan car
Earned a gold trophy in every Career Event
Completed every Career Event in the Invitational category
Completed every Career Event in the Tuner category
Completed every Career Event in the GT category
Completed every Career Event in the Stock category
Won the 'Showdown: Aurora Motorsport' Career Event
Won an Event having finished the first round in last place.
Won the 'Showdown: DisruptR' Career Event
Reached Player Level 99
Won the 'Showdown: Ravenwest' Career Event
Completed every Career Event in the FA Racing category
Won the 'Showdown: Euro Rand' Career Event
Gained entry to the GRID World Series
Won the 'Showdown: Fernando Alonso' Career Event
Won the 'Showdown: Vulpini Racing' Career Event
Reached player level 50
Completed every Career Event in the Touring category
Won the 'Showdown: Hammerhead' Career Event
Finished a race with at least 3 other racers without taking any damage
You customised your first livery
Beat your first Nemesis
Won your first Career Event
Beat your first Career Rival
Purchased your first car
Achieved the Delta Time Objective
Achieved the Fast for a Hatchback Objective
Achieved the High Altitude Objective
Achieved the A Wheely Good Time Objective
Achieved the Burning Rubber Objective
Achieved the British Heritage Objective
Achieved the Flights to Catch Objective
Achieved the Painting the Track red Objective
Achieved the Gone in a Flash Objective