I've been thinking about this too recently, as it seems that with each new physics improvement I get faster in comparison to other drivers. I'm also very smooth, I don't engine brake and I'm very easy on tyres. Of course sometimes I need to push the realism envelope to be competitive, but that's the exception for me.
Again, I have that same issue. I find a lot of the 'fast' guys sets almost undrivable, far too oversteery. I wonder maybe if this is because a lot of the guys came from a drifting background, so it seems natural to them for a car to handle that way. I came from games like N2003, and oversteer at 170mph while your three wide is the end of you.