Ultimate Driver: Achievement PSN of Gran Turismo Sport

Reaching Level 50 will take you many hours – this is potentially the biggest grind in the whole game.
Nearly all racing activities will net you XP, no matter if it is just a Driving School Test or a long online-race. Obviously, the XP granted will be different and reflect the difficulty of the task you have completed. A second source of XP is to finish the tiers of the in-game achievements for different driving milestones.