Used RS4 vs New Golf-R estate

[tonto1]

Needing a more practical car, I'm currently looking at a few options and two of the current front runners are a new Golf-R estate and a used (14/15 plate) RS4. In terms of equipment, both are very similar (BT, nav, leather,, boot space etc), aware the RS4 is more 'car' (bigger NA engine, 7-speed etc), but still trying to decide if the Audi option is really worth ~£15k more.

Any thoughts, experiences, or inputs to the man maths calculator appreciated.