The WRC rules allow for 4X4 on any car. Ford didn't have a 4X4 system for the Focus and niether did the Peugeot, Citreon, Skoda, Hyundia etc.
Remember that Ford and Subaru just sub-contracted to Malcom Wilson Motorsport and Prodrive to design build and run their cars. Ford have now bought things more in-house although Malcom still runs the show.
How about a Prodrive 147/156? I noticed Prodrive Ferrari 550's are running in the LeMans 24.
Other than size it doesn't really matter about the spec of the road car. The WRC cars have no resemblance to the engineering of the road cars. The active diffs, sequential boxes etc all add up to an average of £350000 a car. eek!