I have 60000 miles on my car and the last 40000 miles have had a 4 litre whipple and Ford racing headers and exhaust. Hard on rear tires, Dynoed 770 RWHP at 28000 miles and last fall dynoed 648 RWHP Have a 19 lb pulley and total boost is 20 psi, No real world issues other than tires and routine...