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
Grinding deterministic tracks for the perfect line and the flawless run.

Execution · Pure Mechanics
A pure time-attack arcade racer testing flawless car control on precision platform tracks.
TrackMania 2: Stadium leans Execution (Pure Mechanics); Trackmania Turbo leans Execution (Pure Mechanics).
Trackmania Turbo leans a little harder on execution, though the gap is small.
TrackMania 2: Stadium
Perfect inputs ARE the game - hundredths decide leaderboards
Trackmania Turbo
Platform-racer precision; every millisecond of input matters
Same score on reads - which means the number cannot separate them. The difference is in what each one asks of you.
TrackMania 2: Stadium
Ghost racing - opponents never interact with your run
Trackmania Turbo
Ghost-only competition; no adaptive opponent
Trackmania Turbo leans a little harder on variance, though the gap is small.
TrackMania 2: Stadium
Fully deterministic physics, identical track every attempt
Trackmania Turbo
Deterministic tracks with no hidden randomness
Same score on optimization - which means the number cannot separate them. The difference is in what each one asks of you.
TrackMania 2: Stadium
Finding the optimal racing line is half the hunt
Trackmania Turbo
Finding the fastest line and technique per track is fully solvable
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.