rF is less challenging, due to the unrealistic physics that the mods provide. Of course it doesn't give you an actual challenge with that much power, steering lock and infinite front-end grip. The car moves unnatural, like freaking arcade. I never got around to drift in iRacing, but even powerslides felt crap in the MX5... AC and LFS are kinda on pair in terms of controlling the car sideways. LFS' tires are kinda soapy compared to AC thought (AC is better in that term).