Jim, I made aluminum sled tins that slip inside the 911 shroud and angle to the rear of the car. I had to cut a large hole for the J-tubes that run under the pushrods. Secured the head side with a set of old valve cover bails as I have bolt-on valve covers. Case side has aluminum tabs that attach to 6mm holes in case. Lowered oil temp by 10 degrees F, and cylinder head temp the same 10 degrees. Mine is on a Spyder so no separating top/bottom air. 911 shroud faces forward and tins exit rearward.
I don't know if it would do as much on a Speedster with tins as you already have intake/exhaust separation. But it wasn't expensive to do.