Engine oil cooling?

I have a Bonneville SSEi 3.8L engine and would like to know if an external engine oil cooling could impact engine performance or gas consumption in anyway? I have an oil cool already that is currently plumbing to my rad (GM factory design). If it can be done, where I can buy the oil cooler (not transmission oil cooler type) and how should I do it (which line at the rad I should connect to in series or bypass completely)