This car wouldn't have been competitive anywhere, so this doesn't make sense. The car is not a Group-A car. Heck, it doesn't even appear to be Group-N spec (note the stock Brembos), so why would Citroen pay a WRC Works driver to drive a near stock car from another company, competitively?
As far as I can tell for mods, it's got the cage/race interior, some big-buck dampers, an exhaust, possibly some reinforcement at the front shock towers, some AN fuel line, once had some shields underneath, and other minor stuff. It says "never mapped", so I doubt any anti-lag has been added. No mention of what transmission it has, but with that mileage, I would bet it's still a synchro box.
The photos add *some* credibility to the story, but if Loeb and/or Sainz drove this car, I would think it was used for practice if anything. No word whatsoever on spec or what upkeep has been done, which is extremely harmful to the value of a race car. With a thorough description, overview of history and some actual photos, this car could do well. Until then, it's just a used LHD Evo that's seen 43,000 km.