2010 Subaru Impreza STi Cosworth CS400

𝗛𝗶𝗴𝗵𝗹𝗶𝗴𝗵𝘁𝘀

• One of just 75 Impreza WRX STIs produced in conjunction with Cosworth

• 395hp with 0-62mph in 3.7 seconds

• One owner from new

• Just 54,400 miles

• No-expense spared annual maintenance

• Private plate to match its build number included

• Lovely condition

𝗢𝘃𝗲𝗿𝘃𝗶𝗲𝘄

When Subaru announced a partnership in 2010 with an external tuning company for an upgraded Impreza WRX STI, the expectation was that it would be with long-standing collaborator Prodrive. But for this limited run special edition, of which just 75 were produced, the hardcore upgrade was handled by none other than legendary engine builder Cosworth.

In a comprehensive reworking, changes included suspension improvements, huge six-pot AP Racing front brakes, a beefier clutch and an engine with larger turbo, new con-rods, bearings and pistons which, in conjunction with a revised intake and free flowing exhaust, turning the wick up to 395hp and 400ps giving 542Nm of torque. This extensive list of revisions inevitably didn’t come cheap with the price back in 2010 coming in at a whisker under 50 grand but a substantial boost to the performance and handling, together with the iconic Cosworth name attached, meant that its legendary status was assured from the outset.

The owner of this car previously had the fastest Impreza of the time, the 330S, but when the Cosworth was announced an order was swiftly placed. It’s been serviced annually and exclusively by the supplying dealer, and any advice on maintenance has been followed. This means that when a crack was found in the engine block in 2018, it was replaced with a new short block and the pistons were changed for Roger Clarke Motorsport items, with the bill coming to almost £8,500. Similarly, when the suspension needed a refresh in 2022, Nitron R1 coilovers were installed.

This means that while it’s not exactly as Cosworth originally intended, in reality it’s been upgraded wherever it’s been needed. Cosmetically it’s been well cared for too, with stone chips to the front having been painted, no marks on the wheels, underbody rust treatment and Dinitrol applied November 2023. Inevitably, given that it’s a Subaru beyond a certain age, rear arches are showing very slight emergence of corrosion as small as half a thumb print but it could easily be attended to.

No doubt, if the owner were keeping the car, then it would soon be taken care of but with the car getting less and less use, it’s time for a new owner. So, if you want to experience the most powerful Subaru sold new in the UK, then this is a perfect opportunity.

𝗛𝗶𝘀𝘁𝗼𝗿𝘆 𝗮𝗻𝗱 𝗱𝗼𝗰𝘂𝗺𝗲𝗻𝘁𝗮𝘁𝗶𝗼𝗻

• Registered 20 October 2010

• One private owner from new

• Serviced annually by the supplying Subaru dealership, Simpsons Cars of Swindon with a full set of invoices

• Services as follows: Oct 2010 @1,120 miles, Nov 2011 @5,832 miles, Oct 2012 @11,382 miles, Oct 2013 @16,754 miles, Oct 2014 @22,556 miles Oct 2015 @26,924 miles, Sep 2016 @30,854 miles, Sep 2017 @35,050 miles, Sep 2018 @39,524miles, Sep 2019 @44,735 miles, Sep 2020 @47,926 miles, Sep 2021 @49,980 miles, Nov 2022 @52,015 miles, Sep 2023 @54,079 miles

• The same dealership has carried out almost all repairs and modifications: a new short block (following the discovery of a hairline crack in the original block) with Roger Clarke Motorsport pistons, ARP stud and nut kit, MSport big end bearing in 2018 at 36k miles and Nitron R1 adjustable coilovers in 2022 at 52k miles

• Air conditioning condenser replaced Nov 2023

• The last service was carried out at 54,082 miles in October 2023

• Full document pack

• Two keys

• Current MOT with no advisories expires 25 September 2024

• HPI clear

• ULEZ compliant

• Private plate ‘X19 COS’ matches build number 19 on the Cosworth ID plate

𝗜𝗻𝘁𝗲𝗿𝗶𝗼𝗿

• No stone was left unturned when creating the CS400 and a mild interior makeover was included

• Leather and Alcantara covered Recaros carry an embroidered Cosworth logo and the seats have less aggressive bolsters than the previous range-topper, the 330S, meaning that they are less subject to wear

• The owner, who had a 330S prior to this car, reports that the seats still hold you in firmly and the lack of wear can plainly be seen

• The rear seats have seen only occasional use, and their condition reflects this

• A grey centre maker tops the leather-bound steering wheel and the floor mats (which are in excellent condition, having been stashed away since the car was new) are Cosworth branded

• On the dashboard, there’s another Cosworth logo and there is a Pioneer sat nav and stereo with reversing camera

• Otherwise, the cabin is business as usual for the contemporary WRX STI and is all in fine condition

• The boot is very clean and tidy, the blind in very good order and the spare wheel and tools under the floor don’t look to have ever been deployed

𝗘𝘅𝘁𝗲𝗿𝗶𝗼𝗿

• With a smattering of Cosworth badges, STI front splitter and the addition of a boot spoiler, the cognoscenti will swiftly recognise this as something special

• The stance on its Nitron coilovers is just about perfect, the bodywork undented and the paintwork in excellent condition, following a repaint of the front end to banish the stone chips

• There’s a couple of small issues: a slight chip to the piano black finish on the front grille and a small amount of bubbling on the offside rear arch which looks as if it could be easily treated

• The underside is very clean, having been treated when new and again at 54,200 miles

• Grey-painted alloy wheels are unmarked and wear a matching set of Michelin Pilot Sport 3 tyres which are all in good condition

• Overall, it’s a real credit to its owner

𝗠𝗲𝗰𝗵𝗮𝗻𝗶𝗰𝗮𝗹

• 2457cc turbocharged flat four rated at 395hp

• Six-speed manual gearbox

• SI drive with 3 modes

• Driver Controlled Centre Differential (DCCD) which allows the front:rear torque split to be adjusted

• AP Racing six-pot front callipers

• Nitron R1 fully adjustable coilovers which allow front camber adjustment from under the bonnet; the owner reports that these give an even more planted feel than standard and with a good balance of comfort and handling

• The performance is said to be very lively with the seller describing a much greater well of torque than he experienced in his 330S

• With all maintenance handled by the main dealer and replacements and upgrades in line with their recommendations, this should be even better and more reliable than the standard specification

𝗦𝘂𝗺𝗺𝗮𝗿𝘆

Undoubtedly the most desirable variant of the hatchback era WRX STI, the CS400 is rare and still stupendously quick. This one has been scrupulously maintained and, with its fresh engine and upgraded suspension, performs arguably even better than when new.

To arrange a viewing, please request this in the Q&A section. You can click through to the seller's profile and use the 'Email Me' function to arrange a viewing privately. This seller is located in Swindon, Wiltshire.