[Disclaimer]Let me start by saying pushing is not a bad thing... Pushing/understeering is "safer".... Average drivers are more likely to respond correctly to a car that is pushing/understeering than one that is loose/oversteering.
Changing this tendency in the car should not be taken lightly. If semi experinced drivers like some of us can still screw up and spin in the controlled environment of an autocross with more nuetral cars, you should be very careful about changing the handling of your car for the street...[/Disclaimer]
0. 500lbs of sand in rear cargo area.
134. Move the engine to the center console.
Stiffer rear bar and possibly a rear strut bar will help the wagon a ton as compared to the sedan. Part of the reason Subaru put a softer rear bar on the wagon is because it has more rear weight up higher than the sedan, so to make it push equally bad, they softened the rear bar.
Tires do not actually remove understeer, they just make it harder to reach in the dry. In the wet where not even the RE92s are likely to roll over, everything will still push without changing the suspension, or raising rear tire pressures more than they probably should be.