I remember seeing in a catalog a small 2 or 3 pass oil cooler that was designed for the turbo. I could get one of these small oil cooler for cheap and just was wondering the benefits if there are any?

 

I think upgrading the stock oil cooler would have a better outcome, but even that is not necessary under normal conditions. I can't see how dropping the temp of such a small amount of oil flow could reduce the turbo temps. The exhaust gases passing through the turbo are so incredibly high, 10 degrees cooler oil probably will go unnoticed and just add extra failure opportunities. It's hard enough to keep all the oil in the system as it is. This is just my opinion based on theory not science.