head to head
Dirt 3 asks more than TrackMania United, and the gap is variance.

Execution · Practiced Mastery
Precise rally car control over stages that reward memorisation and tuning.

Execution · Pure Mechanics
A time-trial racer testing millisecond steering precision along studied ideal lines.
Dirt 3 leans Execution (Practiced Mastery); TrackMania United leans Execution (Pure Mechanics).
TrackMania United leans a little harder on execution, though the gap is small.
Dirt 3
Car control on loose surfaces is a high physical ceiling
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.
Dirt 3
Racing the clock or scripted AI, nobody adapts
TrackMania United
Ghost-style multiplayer never interacts with your car
Dirt 3 leans clearly harder on variance.
Dirt 3
Surface conditions and minor physics noise per run
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.
Dirt 3
Stage knowledge and setup tuning reward study
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.