Typically a whine comes from a belt...a oem replacement can cause it, because it does not mesh with the groves in the areas where it makes contact...water pump, ac unit, power steering. Now sometimes those units can be ready to fail and cause the whine. Have you checked the power steering fluid level and be sure you purchase the Porsche required brand here or you will be sorry...refill is (hee, hee...under the hood). To further check and isolate it...get a mechanics stethoscope from your local auto parts store. Have someone race the engine up and down while you listen for the point that you hear the whining. Good luck