Hi, These rubber doughnuts will screw up the handling of the car. (been there and wore the T shirt!) If the springs bottom out on these rubbers you will get some weird effects making the car very unpredictable on fast corners. They are designed as towing assisters to stop the car sagging at the back, and that alone. I think the only way to solve your problem is to get alloys with the correct offsets for your model. Also the larger section tyres are more likely to cause arch fouling if you are close to the offset limits. Larger section tyres on a car this size very often do not equate to better handling. Regards adjustable dampers, if you want to make the suspension stiffer use higher rated springs. Increasing the damping may appear to make the suspension stiffer, but again screws up the road holding, the tyres skipping over bumps on the roads due to slower bump/rebound. Will eventually kill the dampers. Dampers and springs should be a "tuned" pair with adjustment used only to fine adjust for road conditions and driving.
At the end of the day you have to ask yourself ....do you want a cool street low rider or a fast road car that handles well? If its the later you may need to consider the above. Hope this helps.
Neil