Subaru Impreza WRX STI CS400.
What to Check Before Buying.

The Subaru Impreza WRX STI CS400 suits serious performance enthusiasts seeking an exclusive, track-ready daily driver. Limited to just 75 UK units and tuned by Cosworth to deliver 395bhp, this rare variant offers exceptional all-weather performance through Subaru's symmetrical all-wheel drive system and significantly improved power delivery over standard STI models. The CS400's strength lies in its mechanical upgrades including a revised ECU, better intercooler and sports exhaust, though fuel economy suffers considerably with real-world figures often below 20mpg. When buying used, verify the car's authenticity using its numbered build plaque and original documentation, as replicas exist. Check service history meticulously for evidence of regular oil changes using quality fluids, as the EJ25 engine can suffer from ringland failure if neglected or heavily modified beyond Cosworth's setup. Inspect for accident damage given the performance potential, and ensure the six-speed manual gearbox shifts smoothly without crunching. Budget for specialist Subaru servicing costs and premium fuel requirements when considering ownership.

The average used car has 3+ known model faults the seller won't mention.