I've never been fond of station wagon's and am not surprised they're not selling well. I think the liftback is a much more stylish looking car.
235 kw's is okay. If you're after really strong performance you'll need to buy something else and good luck with doing that at a reasonable price.
VXR offers a few extra nice bits over my Calais V. Special seats, (I didn't fit comfortably in them so that ruled me out), Brembo's, adjustable suspension including VXR mode and top line Michelin pilot sport tyres, (although well worth noting that the Continental sport contact 5 rubber on Calais is some excellent kit too).
I think as a handling package VXR makes a good case for itself with the adjustable suspension and VXR mode as well as the Brembo brakes.
Whether its worth the cost premium over a Calais V I am not so sure. Best for buyers to try both and make up their own mind.
Drive a 2.0 RS while you're at it...you might really like the little 2.0 turbo engine and they weigh about 200 kg's less so they're quite nimble.