On the Gen 3 N/A liberties with their rear facing exhaust manifolds an 82mm diameter oil filter was used.
This was also used on early WRX engines (pre-2000 models) and the early RS and B4 twin turbo Liberties that had smaller exhaust manifolds (and may not have had an oil cooler??).
These are the only models that list a different oil filter to later model WRX/Libertys.
On later models the proximity of the oil filter with the larger exhaust headers wrapping around the front of the engine sump, the WRX/Turbo Liberty engines has required a smaller diameter filter to be used. Nominally 70mm diameter.
See image.
http://imgur.com/n8mjsFNAlso, the additional height from the oil cooler unit meant that a short height filter is required, lest the filter become exposed below the headers.
Reference your other post and questions regarding a larger capacity filter
viewtopic.php?f=7&t=31290&p=418360#p418360.....
A taller filter like the one for FB engine Impreza/Forester could be used, Ryco Z411. However, both the under body clearance to the plastic splash tray and protection from possible mechanical damage from under car obstacles would need to be confirmed.