I just installed my G-25 brake pedal mod from Nixim and it is awesome. It is a little rubber bit that fits inside the spring and housing of the controllers brake pedal and makes it feel much more like a real brake pedal. It was around $17 delivered and worth every penny and then some from www.nixim.com
I still have to recalibrate the actuation point of the brakes so it is properly tweaked for rFactor but initial laps with no calibration were far better. Anyone that uses a G25 should get this mod. I have the boys at CXC Simulations to thank for recommending it and pointing me in the direction to get it.