Yeah sadly swapping is out. Reverend and others have even tried. Maybe someone will wreck an xv and some seats will come up for sale. I know the padding in my xv's seats is way more supportive than my Impreza's. These are even *comfortable*. But if you did somehow find a deal on xv seats, make sure you try them.out at a dealer first. you may not find them to be an improvement.
The seats were so bad in my impreza, I wouldnt have bought the xv if it had the exact same.