Here is the full list of all 35 GRIP achievements.
Perform a double-somersault when airborne
Destroy an opponent
Finish an arena match
Destroy 2 players without dying
Destroy 3 players without dying
Hit only vehicles with every Hydra missile in a salvo
Hit an opponent with a Scorpion launched when airborne
Hit an airborne opponent with the Scorpion
Finish 1st 3 races in a row
Finish 1st in a race
Finish a race
Finish the tutorial
Finish a 20 lap race
Race 100 laps in total
Race 2500 laps in total
Race 10000 laps in total
Finish 1st 6 races in a row
Go from 10th to 1st within one lap
Average a speed 700kmph+ in a race
Hit 3 or more opponents with a single charged RamRaider
Hit Mach 1 in a race
Destroy 4 players without dying
Destroy 5 players without dying
Destroy 50 opponents
Destroy 500 opponents
Destroy 1500 opponents
Finish a carkour course
Finish all carkour courses
Finish the campaign
Create a custom tournament
Pull a wheelie on the ceiling
Hit an opponent with a full round of Raptor bullets
Destroyed some scenery
Win a race by passing the leader in the last second
Hit 3 or more opponents with a single Hydra