Q: My car is all stock. I do not plan to lower it. I want 20x9 or 20x8.5 rims. Most likely they will not be ultra low profile tires. Have any of you done this and had no problems.
A: Any problems? Just one ( and I have actually witnessed the result on one E-Class ). Part of the suspension dampening on any vehicle are the tire sidewalls. They help absorb small bumps and road irregularities before they are transmitted through the vehicle's other suspension components and chassis. In the case of this one E-Class, they had put 20 inch rims on and the tire sidewall ended up being so thin and stiff that pretty much every bump and pothole was felt throughout the rest of the chassis. The driver of this E-Class drove over a pothole and the shock of that dip triggered the side crash sensor and deployed both the side airbags and roof curtain on one side of the car. I've only seen this happen once and it is an extreme example but be aware that it can happen.