I have no idea what the part number could be but from long experience with alternate airfilters, mainly on motorcycles but also on cars, I can assure you that the gains are largely imperceptible. The main gain is that you can confidently tell people that you have a high flow air filter. What you don't tell them is that it only gives a better airflow when clean, particularly if it is the oiled type, and that it can actually cause mixture problems that defeat the carefully tuned intake system and and fuel mapping. The feedback from the sonda lambda largely compensates but under some circumstances the fuel/air mix will wrong.

Oiled filters work well when cleaned and freshly oiled but the oil quickly catches dirt which clog the filter, this in turn will reduce the airflow below that of a standard filter. I would not recommend any oiled filter for road use for that reason.

I would say save your cash and keep using the relatively low cost replaceable airfilters which do a good job and are matched to the engine.

If you want more power and torque you would be better off investing in a sports exhaust system. This will also throw out the fuel map but you will gain some performance and the sonda lambda feedback system should cope with most of the variation. I don't think re-mapping the GDI system is possible at the moment becuase of the complex layered injection pulses.

Librands have a system for the Plus 4 GDI.
http://www.librands.co.uk/products-view-184.html

Peter

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