Which Brake Force setting are you using? I am deciding between 40 or 50. Can you clarify about the throttle spring? I did not change anything, will check it up.
I'm using 90 or 95 if i remember correctly, however the value to use will depend on a couple of factors; how hard you want to engage your leg, if the brake performance kit is installed, which combination of rubber bits from the performance kit, driving technique, etc.
The easiest way to find a suitable brake force setting is to go into the Fanatec wheel properties where you calibrate the min and max settings. Play around a bit the brake force value in the tuning menu while depressing the pedal to see how it affects the calibrated value.
I have not seen any official instructions on how to set the brake force correctly but this is basically how I did it when calibrating the brake pedal from scratch, hope it makes some sense:
1. Go into the tuning menu on the wheel and set brake force to som arbitrary value, i.e. 60
2. Open Fanatec Wheel Properties and enable manual calibration of the pedals
3. Rest your foot on the pedal as you would while driving and not braking
4. Press "Set min" in the interface
5. Press the brake pedal really hard, just too ensure maximum travel at the end point (remember it's the force and not travel that matters when ising the brake). While doing this, watch the meter showing the brake sensor value.
6. Press the brake a couple of times again, applying approximately the force you want to use for example for 50% braking, 75% braking and 100% braking
7 a) If the brake seems to bottom out way too easily during step 6, the brake force setting in the tuning menu is too low and should be increased.
7 b) If the brake does not reach max value or if it seems way to sluggish during step 6, the brake force setting in the tuning menu is too high and should be decreased.
8. The reference point for which brake force value is most suitable is probably where you can apply 100% brake without discomfort.
9. Verify that the brake calibration in ACC settings (and every sim) just to ensure no sensitivity settings in the sim interferes with the new calibration.
Repeat step 3 & 4 if necessary if the brake force value has been lowered.
Regarding the throttle spring:
There are two extra black springs included with the pedals, one for the throttle and one for the clutch. They are stiffer than the original red ones installed, hence giving more resistance. It's simple to switch the springs, only two screws on the throttle pedal, just be careful not to pinch your fingers when putting it back together. Check out Sim Racing Garage's video on how to change: