They are different. I'm loving them all. They compliment each other.
The XJ is a fast comfortable luxurious car: a mobile carpet or a lounge on wheels
The D3 is fast, economical, quiet and relatively comfortable for its 19" alloys
The STI is fast and furious, surprisingly more comfortable than the D3, and loud :P
When I first drove the STI with my boyfriend and after a couple of hours when we came back and stop the car, he said to me: "I'm getting a headache, just turn the engine off; I want some quietness!!!"
I see other people's reaction:
When I drive the XJ, they may jump in front of me sometimes, as they think..."an old man's car...bah won't be going fast..."
When I drive the D3, they pull over out of my way B)
When I drive the STI, they don't even think to get on my way