hi i have bought a st170 but it came with a open air filter so i want to fit standard air box as iv read up that its better this may be a stupid question but does it have to be a st170 air box or do any other focus engines use the same air box like a 1.6 or a 1.8 i should imagine it would be different but i thought it would be worth asking thanks

 

If you havn't found the answer yet the st170 box in different. You will need the air box, snorkel and its worth also fitting the deflector (plastic slam pannel) from a 2l auto focus as that allows cold air in from the top grill rather than the tiny gap between the bonnet and slam pannel.