I need to replace my power rack and pinion on my 92GT. Should I go with a AGR Unit 15:1 ratio from SummitRacing or should I just go to the auto store and get a remanufactured one and call it a day. Also, if I go with the AGR unit do I have to purchase the AGR power steering pump or can I just use the Motorcraft Unit that is already on the car which is only 2 years old? Thanks.