I need to replace the pump on my 95 RMW and want to go AC delco. I see rock auto has 2 pumps listed for my car. One mentions a stamped steel impeller with the same P/N as in the sticky, costs $176 and says OE design. The other is also a Delco (88926214) that costs $82, but mentions it has a cast iron impeller. I'm tempted to buy the cheaper one but am wondering if there will be any long term issues with a cast iron impeller which I assume is heavier than the steel one. Anyone ever used this one?