I believe high end pedals can certainly improve times, more than a high end wheel can. And many of the FF effects in wheels are actually replicating the undesirable effects that real race engineers want to remove from the car. Maybe feeling the back end go out or the front wheels locking up can help you go faster, but then again if you're driving over the egde and making those kind of mistakes you aren't going to be WR fast anyway.
If you think about it, FF effects will make the car slower: as the wheel jolts around it will subtly move the front wheels of the car from the optimal path, which will scrub speed. Turn it off completely (use centreing sping) if you want ultimate speed. In fact I discovered in LFS that you could get a (very slightly) higher top speed with keyboard control compared to a wheel or other analogue controller - with the keyboard being digital there is a centering mechanisim which stops the steering / front wheel moving at all when in a straight line. Analogue steering constantly moves around the centre point, subtly moving the front wheels, again therefore scrubbing speed.
If you think about it, FF effects will make the car slower: as the wheel jolts around it will subtly move the front wheels of the car from the optimal path, which will scrub speed. Turn it off completely (use centreing sping) if you want ultimate speed. In fact I discovered in LFS that you could get a (very slightly) higher top speed with keyboard control compared to a wheel or other analogue controller - with the keyboard being digital there is a centering mechanisim which stops the steering / front wheel moving at all when in a straight line. Analogue steering constantly moves around the centre point, subtly moving the front wheels, again therefore scrubbing speed.