I'm wanting to know if their is a difference in the operational specs of the S5 and S4 T2 fuel pumps? Unfortunately, it looks like I need to go back to a stock pump for now. I can get an S4 T2 pump from a friend or I can buy an S5 T2 pump. If I can get away using the S4 T2 pump that would be great. Can anyone help me out here?