I believe to successfully lower my Forester I require:

Impreza Front Subframe Bolts

Impreza Transmission Mount

Impreza Front LCA Mount

Impreza Rear Antiroll Bar Mount

Impreza Gear Linkage & Bushings

Impreza Steering UJ

Or just buy some coilovers, mines lowered by 2" so not stupidly low and still retains enough clearence for speed bumps etc, depends how low you wanna go or what 'look ' your after. The transmission mount is the same along with all control arms etc so I can't really see what benefit swapping those out would have, the rear arb mounts are about an inch lower on the impreza, I've been told there is a subframe spacer on the foz which isn't on the impreza too

Long story short, all the above allow the Forester to be lowered without affecting the suspension geometry too much.