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.
Reached Player Level 99
You won a race in a Ravenwest livery with Nathan McKane as your team mate
Purchased at least one car in each class
Won the 'Showdown: Ravenwest' Career Event
Earned a gold trophy in every Career Event
Completed every Career Event in the Invitational category
Won the 'Showdown: Aurora Motorsport' Career Event
Completed every Career Event in the GT category
Won the 'Showdown: Euro Rand' Career Event
Won the 'Showdown: DisruptR' Career Event
Gained entry to the GRID World Series
Completed every Career Event in the Tuner category
Completed every Career Event in the Stock category
Won the 'Showdown: Vulpini Racing' Career Event
Reached player level 50
Completed every Career Event in the FA Racing category
Won the 'Showdown: Fernando Alonso' Career Event
Completed every Career Event in the Touring category
Won the 'Showdown: Hammerhead' Career Event
Won an Event having finished the first round in last place.
Won an Event with at least 3 other racers using a loan car
Finished a race with at least 3 other racers without taking any damage
Won a race by crossing the line backwards
You customised your first livery
Beat your first Nemesis
Won your first Career Event
Beat your first Career Rival
Purchased your first car
Drive a total distance equal to the circumference of the Earth
Complete the High Altitude Objective
Complete the Delta Time Objective
Complete the Fast for a Hatchback Objective
Complete the British Heritage Objective
Complete the Burning Rubber Objective
Complete the A Wheely Good Time Objective
Complete the Gone in a Flash Objective
Complete the Painting the Track red Objective
Complete the Flights to Catch Objective