67autocross
A new iron curtain drawn across the 49th parallel
To me it sounds like what most solid axle cars do when they hit a sharp bump mid corner, they do this little skip/hop. My 2012 Mustang Gt does this just like an old Mopar does, but the new car has balanced suspension and settles back quickly.
Looking at what you have done to your Duster I would guess ( because it could be anything causing this ) that the front is a lot stiffer than the back and when the rear skips over something mid corner it starts whipping around due to the suspension not being balanced, stiff front, soft rear. So the first thing I would do is install the rear sway bar that goes along with your kit suspension system.
Low profile tires do change a lot of the characteristics of a car but I don't think they are the problem in this case, but you might feel the problem more because of them.
Let's us know how the test drive goes and report back!
Looking at what you have done to your Duster I would guess ( because it could be anything causing this ) that the front is a lot stiffer than the back and when the rear skips over something mid corner it starts whipping around due to the suspension not being balanced, stiff front, soft rear. So the first thing I would do is install the rear sway bar that goes along with your kit suspension system.
Low profile tires do change a lot of the characteristics of a car but I don't think they are the problem in this case, but you might feel the problem more because of them.
Let's us know how the test drive goes and report back!