Some more things to check:
Steering lock (too sharp and it will only assist the spins)
Engine braking (too much, too little, it can both help or make it worse so experiment)
Decrease Anti-roll for more stabillity
Lower rear Brakedisc will help with snap-oversteer (keep front high)
differential lock/coast settings, experiment to make the car less nervous.
You could also check if a different degree in the wheel itself helps out. i've seen people gain allot of time and consistancy just by going from 200 to 360degrees.
But even with everything unstable you should be able to keep it on-track. its just the imput you give, probably overdriving the car, wanting to go too fast too soon. I suggest a whole bunch of laps on 80% and build up when confidence is building.
And yeah, dont gear down too fast.
In fact, use the gears to your advantage, sometimes you want to gear down to 1st when allready well into the turn simply because the gear-down/engine braking can assist you in apex-stabillity.
Maybe go to rcentral/the mod you are using and see if there are setups available? allways handy imo.