Volvo V70 SE Lux D5 or D4? or Audi A6?

michaelandkerry

I have an 8 yr old V70 and am considering updating.  Have considered Audi A6 Avant and Skoda Eleganz, but think I will stick with Volvo - but which one? 

Is D4 with same bhp (163) but smaller engine than my current D5 powerful enough?  Or woul;d D5 be better?  Anybody any experience of these cars?

We tow a Unicorn Seville.