The springs from the SS addition is the most unresolved item's from the whole kit, the springs are too stiff which highlight the dampers being a bit too soft so you get a really hard ride with no damping, meaning a car which is slower in the bends as the suspension doesn't move meaning it fails to keep the wheels in contact with the ground. Though I admit it looks better.
Yes it has no roll, but you really need to understand suspension to realise some roll is needed to make the car turn in better, it just feels unnatural to us humans especially if sat in a seat the offers little support to stop you moving around.
If you want to lower a 500Abarth find an alternative and make sure it includes dampers. Some height adjustable suspension is not as expensive as at first expected, I think V-Maxx Dutch company are doing a full kit including a rear height adjustable platform (it is not coil-over at the rear remember as the spring is separate from the damper) for about £550 for fixed rate dampers, more expensive with adjustable.
In my experience manufacturers will still honour warranty on a car with modifications just not on the area of the modifications themselves, ie you fit new dampers and springs, they are not going to say we are not going fix that turbo that has blown because the dampers did it.
But you can check with your local dealer first as they may be more receptive than you believe.
