Interesting subject but suggest we divide it into at least 2 parts:
1. engine cooling (and trans)
2. engine bay cooling
The engine and trans cooling has been discussed already .
The engine bay cooling obviously concerned Porsche hence the engine compartment fan. Heat soak also an issue. Logically just increase the size/efficiency of the engine compartment fan+ducts.
See post #5 in the link for ideas but be wary of causing codes.In theory you could wrap the exhaust to reduce radiant heat in the engine compartment &/or reposition the engine compartment temp sensor to a hotter location so it comes on sooner/stays on longer ?
High speed fan relay hack/mod - 996 Series (Carrera, Carrera 4, Carrera 4S, Targa) - RennTech.org Community
"Engine Compartment Fan Connect a wire to the ground of the relay located in the relay carrier behind the passenger seat, driver’s side. Relay #8. . Feed this wire to where your switch will be located. I simply fed the wire along the driver’s side of the car and under the door sill. Connect the wire to one side of the switch. Connect another wire from the other contact on the switch and connect the other end of this wire to a chassis ground point. With key on, this switch will now immediately turn on the fan drawing air into the engine compartment. When you turn the key off, the fan will continue to run for about 5 seconds until the relay shuts down. Your fan operation remains normal when the switch is off. This mod helps keep the engine compartment much cooler when driving around town and is particularly beneficial to any engine that draws its intake air from inside the engine compartment, such as the EVO SC. If you are adventurous, you can automate the operation of these switches so they will switch off at a specific speed, or operate when vacuum is present only, etc. You can choose any style switch you want and even use Porsche switches. I simply used 2 toggle switches that I installed in the batwing, Jim"