Its a bit of a 'left field' choice but I have a black SS commodore with 480hp stage 2 weight reduction, sports suspension and comfort hard tires.
This when combined with a narrow road technical course maker (random on toscana) will teach you about changing the cars attitude. Due to the randomness of the road you have to learn to react and change from under/ovetsteer in between corners.
When you finally go on a circuit the extra space is a revelation, I can reccomend the Cape Ring and Autumn Rings as two of the best.
Just keep trying RWD cars with comfort hards, when the speed and feel builds start moving to sports and racing tires and check the excellent tuning section here for set ups and cars.