Thanks for all the advice guys.
Things that made difference for me:
4x sparse grid supersampling and the other things troy mentioned are magic: even though my average fps has gone down the game has gone from a blurry, washed out, flickering, inconsistently stuttering mess to to a crispy clean, smooth flowing, fantastic looking sim.
This combined with lowering the FOV to 50° has allowed me to actually see where the track is going and lets me get an idea where my car is heading.
Going really low on the FFB gain also does its part in letting me fight the car instead of the wheel.
One thing I'm really enjoying with the DTM M3 at Imola is the way the rear of the car dances around controllably under heavy braking, something I haven't felt in a sim before.
Also the way the balance changes between on and off throttle is great.
Tristan, what happened? Violent snap-back oversteer?