The best ever impreza is a tough one. He's my favourites anyway.
(1) The P1 - also has as standard suspension by Prodrive (they tried every possible combo from the DTi springs and dampers catalogue), optional Alcon brakes, Optional 18 inch P1 wheels (over the std 17 inch P1 wheels, Optional Prodrive seats with fully electric adjustment and optional HID lights. It is also 280ps on 97 octane!
(2) Litchfield Type 25 and type 20.
(3) Impreza S 204.
Frawls