Saab use the standard filter on the 260hp 9-5 Aero.
Hirsch fit a slightly bigger filter in a similar air box when they go to 300 hp. But their work is sometimes a bit over the top. The tunes need to work in all markets the car was sold, including hot and dusty parts of the world.
However, Karl at Noobtune did some back to back testing and reckons that a better flowing filter will give some small gains. You might want to consider one of his tunes.
www.noobtune.co.uk Abbott are not noted for their work on the tuning if the later engines. Their hardware is fine though.
A bigger air filter should be fitted, and shielded if necessary, to prevent it drawing in hot air from the engine compartment. Otherwise some of the cooling effort of the intercooler will be lost. But this only seems to be a problem in congested areas with traffic jams.
