head to head
vs
Gran Turismo 4vsrFactor
Gran Turismo 4 leans Execution (Practiced Mastery); rFactor leans Execution (Practiced Mastery).
Gran Turismo 4rFactor
Axis by axis
Execution8 vs 8
Even - both lean on execution about the same.
Reads0 vs 1
rFactor leans harder on reads: Online wheel-to-wheel racing adds slight opponent prediction
Variance1 vs 1
Even - both lean on variance about the same.
Optimization7 vs 6
Gran Turismo 4 leans harder on optimization: Event-by-event car and tune selection is deeply solvable
Two games can score the same on an axis and still test it in very different ways - read each rationale, not just the number.