Just been browsing the 987 tequipment on the web...

PCM:

In cases of extreme outside temperatures, the temperature in the luggage compartment can reach over 85 *C, which could lead to a possible switch-off of the navigation drive and thus to a shut-down of the navigation module. If the need arises, a luggage compartment cooling system can be fitted to prevent such switch-offs.
Part no. 997 044 900 79

Be interesting to see if that turns the whole front luggage compartment into a big beer fridge