C30 ventilation adaptor
S40 ventilation adaptor
V50 ventilation adaptor
C70 ventilation adaptor
 
Screws inside the dashboard to have an airchannel out to the front with a Ø50mm pipe between the front part and heatercore.
No modification needed, just two screws to hold it in place as pictured on the sides.
The screw holdes have nothing to say if put back to standard setting. The plastic they screw into is just a partial blind for the stock heater duct.