[elhigh]

36 in an Impreza is amazing. My Forester won't get better than 25.

You can make some alterations, but you'll have to be sneaky.

You can add aero improvements like a belly pan; she'll never see it.

A really well-done set of fender skirts that look factory will help a bunch. If you can cover her wheels to reduce their aero resistance, that'd be good.

Taking out the spare might have been a wrong step. If she's covering 100 per day, her commute is probably pretty long and on highways; weight reduction is good in town but doesn't contribute as big a savings when cruising.