If you're referring to this:http://www.newegg.com/Product/Product.aspx?Item=N82E16814150491&Tpk=xfx%205850
That's a non reference cooler already. It has what looks like to be a few copper heatpipes leading to either an aluminum or copper heat sink and a fan. The only problem with this cooler that some don't like is that it's spitting the heat inside the case instead of outside the case as the reference ATI cooler does.
Dropping the temperatures on your video card will ensure greater stability over the life of the card, yes. It can also allow for safe overclocking for increased performance too.