This isn't true for the SL500 at all, and I would venture to say not for performance cars in general. The SL500 is a pig at nearly 4,000lbs and has way too much torque and horsepower, and as a result, oversized parts which aren't made for normal driving. As the "performance" of the car ramps up, so does the difficulty of handling the car. A possible exception to this rule is AWD cars.