head to head
Neither is meaningfully harder - they pose close to the same test. The widest gap is execution, and it is a single point.

Execution · Pure Mechanics
A pure time-attack arcade racer testing flawless car control on precision platform tracks.

Execution · Pure Mechanics
A time-trial racer testing millisecond steering precision along studied ideal lines.
Trackmania Turbo leans Execution (Pure Mechanics); TrackMania United leans Execution (Pure Mechanics).
Trackmania Turbo leans a little harder on execution, though the gap is small.
Trackmania Turbo
Platform-racer precision; every millisecond of input matters
TrackMania United
Hundredth-second steering precision over stunts decides every leaderboard
Same score on reads - which means the number cannot separate them. The difference is in what each one asks of you.
Trackmania Turbo
Ghost-only competition; no adaptive opponent
TrackMania United
Ghost-style multiplayer never interacts with your car
Trackmania Turbo leans a little harder on variance, though the gap is small.
Trackmania Turbo
Deterministic tracks with no hidden randomness
TrackMania United
Tracks are perfectly deterministic
Same score on optimization - which means the number cannot separate them. The difference is in what each one asks of you.
Trackmania Turbo
Finding the fastest line and technique per track is fully solvable
TrackMania United
Finding the ideal line is a study discipline of its own
A matching score does not mean a matching test. Two games can both sit at 10 on execution and demand completely different things of you - which is why the reasoning above matters more than the number beside it.