ksimpson

I'm currently looking at a C4S which has the Aerokit. The car is ex UK now based in Ireland. It has the rear wing which I've seen on other C4s', but also has vents in front of the wheel arches on the rear fenders which I haven't seen on other 4s' with the Aerokit. Was this a factory option or something one of the owners would have added? I presume they are to aid brake cooling or are they purely esthetic?

Gert

These side air intakes are the Turbo S intakes.
I believe this is an owner installed option.

The installation of the air intakes require to repaint the rear quarters.

Pay extra attention when you inspect the car as this kind of modifications is usually done together with other bodywork.

ksimpson

Yes that's it exactly. Was that a factory option or after market?

Mike in Chi

The factory option offerings were quite extensive then. It also could have been a customer request done by the factory.

Is there anything on the option code sticker?

VerySideways

This was a factory option - Autocar reported it as an option on the 1997 Porsche 911 Carrera 4S "Exclusiv". Porsche Cars GB even did a show car with every available option (Turbo S rear wing, etc).

These "nostrils" in the rear quarter panels were about £3000 on the factory options list!!!

I'm sure your local OPC will be able to tell you if this was factory fitted or aftermarket if you give them the chassis number....

Edited to add:
I know they were present on the Turbo S to provide more air for the forced induction system, though i don't know if that's to cool the engine, turbos, or intercooler. Nothing to do with brake cooling though.