Stock suspension is fine for me, my 94 year old father and my 90 year old mother. I had my alignment checked and had the toe adjusted on the right (actually left) front which greatly alleviated the YAW you have described. My right rear is still out of specs and that is not adjustable through any normal process except actually bending the rear stub axle which is welded to the axle beam.
It's like an airplane when you move the rudder (vertical stabilizer). the plane flies somewhat "sideways". This is the instability you are describing.
Get the alignment checked. No matter what you do to the suspension, it must be properly aligned or it will never handle correctly.
Last edited by deleted user; 07-10-2015 at 06:02 PM.
View my fuel log 2015 Mirage de 1.2 manual: 55.7 mpg (US) ... 23.7 km/L ... 4.2 L/100 km ... 66.9 mpg (Imp)