Water Pump Question - '86 K10 -

[WDE86]

My water pump has gone bad and I've noticed that these are made out of either iron (standard ones) and some companies like Edelbrock make aluminum ones. I'm wondering is it worth spending the extra dough on an aluminum "performance" one? Or should I get the standard iron pump and maybe spray on a coat of high-temp paint to help keep it from rusting so badly? The one that went bad for me recently was only three years old and very badly rusted.