At 2000rpm, both these cars are bogging *terribly*, both making ~40rwhp, ~102 rw-lb-ft.
2000rpm in 1st:
FR-S/BRZ torque at wheels = 102 lb-ft * 3.626 * 4.1 = 1516 lb-ft
AP1 torque at wheels = 102 lb-ft * 3.634 * 4.1 = 1519 lb-ft
2000rpm in 2nd:
FR-S/BRZ torque at wheels = 102 lb-ft * 2.188 * 4.1 = 915 lb-ft
AP1 torque at wheels = 102 lb-ft * 2.372 * 4.1 = 992 lb-ft
2000rpm in 3rd:
FR-S/BRZ torque at wheels = 102 lb-ft * 1.541 * 4.1 = 644 lb-ft
AP1 torque at wheels = 102 lb-ft * 1.718 * 4.1 = 718 lb-ft
That's going by these rear wheel power/torque curves:
3500rpm looks like 128 rw-lb-ft for the FR-S/BRZ, 119 for the F20C, easy enough to apply to the gear ratios given above.
3500rpm in 1st:
FR-S/BRZ torque at wheels = 128 rw lb-ft * 3.626 * 4.1 = 1769 lb-ft
AP1 torque at wheels = 119 rw lb-ft * 3.634 * 4.1 = 1773 lb-ft
3500rpm in 2nd:
FR-S/BRZ torque at wheels = 128 rw lb-ft * 2.188 * 4.1 = 1068 lb-ft
AP1 torque at wheels = 119 rw lb-ft * 2.372 * 4.1 = 1157 lb-ft
3500rpm in 3rd:
FR-S/BRZ torque at wheels = 128 rw lb-ft * 1.541 * 4.1 = 752 lb-ft
AP1 torque at wheels = 119 rw lb-ft * 1.718 * 4.1 = 838 lb-ft
FA20 does have a bigger torque advantage between 2000 and 3500, more so than at those specific rpms. Plug in values at 3000 and the FR-S/BRZ will look better there. But then worse from ~3500-4500