I installed the Stewart Warner oil cooler on the left intake, engine forward location. I placed it here based on some recommendations of others. You can just see the flapper door mounted to the bottom. A control cable in the cockpit will allow me to control the oil temperature remotely.
I made my own hoses using Aeroquip hose and mandrels. It is a simple process. All parts purchased from Aircraft Spruce. I have the directions on the download page. The cost is about the same to make them your self initially. But once you make 5 or six of these, which I will with both the oil and fuel system, you quickly begin to recoup the costs.