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

Execution · Pure Mechanics
Open-world racing testing car control and line discipline with light tuning underneath.

Execution · Practiced Mastery
Cornering execution over memorisable circuits, with light prediction in wheel-to-wheel multiplayer.
Forza Horizon 2 leans Execution (Pure Mechanics); Grid 2 leans Execution (Practiced Mastery).
Same score on execution - which means the number cannot separate them. The difference is in what each one asks of you.
Forza Horizon 2
Racing lines, braking points and car control lead everything
Grid 2
Car control through corners is the entire moment-to-moment test
Grid 2 leans a little harder on reads, though the gap is small.
Forza Horizon 2
Drivatar AI mimics styles but stays effectively scripted
Grid 2
Online wheel-to-wheel adds light positional prediction
Same score on variance - which means the number cannot separate them. The difference is in what each one asks of you.
Forza Horizon 2
Weather shifts grip slightly; courses are fully known
Grid 2
Tracks are fixed and fully visible
Grid 2 leans a little harder on optimization, though the gap is small.
Forza Horizon 2
Car tuning and route knowledge reward preparation
Grid 2
Racing lines, braking points and car selection are studyable
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.