I run the Milwaukee Twins Dual Cool, A-Frame style cooler, with the Jagg 4600 twin cam adaptor(with anti rotation device-its a MUST). The cooler isnt as effective as the radiator style, but it very sharp looking and does considerably reduce the oil temperature. The Jagg adaptor is a breeze to install, just note the position of the Anti-Rotation bracket, because you have to install the inner plate of the adaptor first, then put the outer plate on which holds the Anti rotation thingy.

 

Also had some nice Stainless braided lines made with JIC fittings for the install. Very sharp, but a little pricey.

 

I ride in cold weather below 30 degrees sometimes. Marv at Jagg still said I didn't need one.
Their website in the FAQ says they are not needed.