Nothing.
I previously owned German or Swedish cars in England and this is the first Japanese car that I have owned and I am not overly impressed.
Most of them seem soul less, but I thought the Impreza might be different.
They call it a wagon, but really it is a hatchback, Room in the boot is OK, but not amazing.
There is not much room inside, I am not a big bloke, 176cm (5ft 10ish), but it is still cramped.
The interior is very plasticky and cheap looking, although I have to say it doesn't rattle.
The air con struggles on really hot days.
It is gutless (manual may be better). You have to floor it to make it kick down.
Parts and service seem to be expensive, cheaper to run my old Saab I reckon.
You may be disapointed to find that your Saab and your Subaru are made by the same people...