1990 Ford Sierra RS Cosworth

This fine example of the 304-R Rouse Sport model is build number “29 of 100” (which actually topped out at 78) and was completed on the 18th of October 1990. A fair number of owners followed but the mileage has remained impressively moderate for the age of the Cosworth. The previous owner acquired the Sapphire in December of 2018 with the odometer standing at a shade of over 85,000 miles at that time.

Current owner, Darren, acquired the Sierra Sapphire Cosworth at auction in September of 2025 to become its 12th registered keeper. Just 86,100 miles were recorded at that time with today’s total standing at just 86,423, equating to just under 2,500 miles per year on average. 

In previous ownerships a raft of performance improvements has been wrought to further augment the original’s 260bhp and 300 Ib-ft of torque. These upgrades include DB10 camshafts; a T34 stage 3 hybrid turbo; a Group A head gasket; a Collins Performance stage 3 chip and board; a 3-bar map sensor and Grey 403 injectors; a two-stage boost switch; a Pipercross air filter and aftermarket dump valve; an aluminium header tank and a Mongoose stainless steel exhaust. 

The owner also informs us that a Cat N insurance marker was attributed to the car in 1994, though it was successfully inspected following repairs. Interestingly our accompanying My Car Check report makes no reference to this.

By 1990 the Sierra Cosworth had matured somewhat from its 3 door, whale tailed, wild child youth to a more restrained Sapphire four door saloon which offered all the usability and practicality of Ford’s penultimate saloon offering. Some hang overs from its lad about town stage remained, of course, especially in this super-rare Rouse Sport version. The special edition body kit fitted by Rouse included a surprisingly deep chin spoiler, chunk, rounded side skirts, a more bulbous rear bumper cover and a generous boot lid spoiler. As if more clues were needed about the apex predator credentials of this Sierra, there are numerous Rouse Sport badges and decals dotted about. These adorn the boot lid, rear valance and both ends of the black rubbing strips down each side.

The Arctic White livery of this example lends it a crisp, 90’s appropriate character as well as an impressively lustrous shine. Owner Darren notes that the Cosworth has been ceramic coated which clearly helps. White front indicator lenses have also been fitted to further emphasise those arctic vibes. The glass sunroof and headlamp wash / wipe system also serve as a reminder as to how well specified these cars were by 1990’s standards.

The 16-inch, five spoke alloy wheels are of the type shared with the Escort Cosworth and appear to be in a good condition overall. There’s a modicum of kerb rash in places, but this is only really noticeable on close inspection. A mixed set of 205/45 configuration tyres are fitted.

This Ford Saphire’s cabin is notable on account of its sublime and supple looking black, perforated leather upholstery. The heavily bolstered “wing-backed” Recaro front seats are even adorned with Rouse Sport emblems which almost distract one from the very subtly embossed “Recaro” name. The condition of these is impressive in the context of the car’s age and mileage. The rear bench is finished in the same impressive, perforated leather and helps to underscore the surprising practicality of this most performance orientated of fast Fords.

Black leather door cards and grey / black carpets accompany the leather and appear to be in a commensurate condition throughout. The light fabric headlining looks clean and well fitted, and the original sunroof blind is even present and correct. The straight edged gauges in the main binnacle are white faced and sit behind a three spoke leather steering wheel with more Rouse Sport branding. The centre console is topped by a pair of ancillary gauges (boost and oil pressure). Below this the original Ford RDS (remember that?), radio cassette head unit is still charmingly present.

Upon opening the driver’s door a blue and silver Rouse Sport plaque can be seen in the bottom left corner of the jamb. This helpfully records the chassis number, build number completion date and model number. The impressively large boot is trimmed with an original looking black carpet mat.

The Sierra Sapphire Cosworth Rouse Sport was equipped with the standard car’s 1993cc four cylinder DOHC, 16-valve turbocharged engine. Revised mapping, inlet improvements and a lighter Garret turbo in the Rouse Sport added around 40bhp to the standard set up’s 220bhp. This car, of course, as previously touched on has enjoyed further well-chosen performance upgrades in subsequent years to further enhance those impressive original KPIs. 

Lifting the bonnet reveals references to both Cosworth and Rouse. The blue finished head is embossed with both Ford and Cosworth logos and the original suspension brace adds Rouse Sport to the mix. There is also Cosworth branding to the plastic timing belt cover. The condition under here is very good with clean and corrosion free inner panels and a nicely insulated bonnet underside. The underside of the car appears to have been extensively undersealed in recent years with most of the surfaces remaining well finished and protected.

The paperwork archive starts with the V5 registration document in the name of the current owner. The current MoT is present in hard copy and remains valid until July 2026. Numerous earlier MoT hard copies are also present providing a useful audit trail of this car’s moderate original mileage.

Other highlights include some fascinating Rouse Sport documentation including a welcome letter from the man himself. There are also extracts from the original brochure and other specification summaries. Some of the original book pack is present as are an impressive number of invoices covering all period of the Cosworth’s life. A fascinating archive which is well worth studying at your leisure.

Fast Fords are highly desirable nowadays and only seeming to become more so as the supply of good examples inevitably shrinks. Of course, some fast Fords are faster than others and the Sierra Cosworths have long stood at the top of the tree in terms of power, performance and prestige. Even then there is a Cosworth pecking order with the “standard” cars being produced in surprisingly large numbers. It is the rare, low-volume cars, therefore, that get the Ford fans in a frenzy and with just 78 ever produced the Rouse Sport Sapphire must be amongst the best.

We are happy to offer this car for auction with an estimate in the range of £20,000 - £25,000.

This example of the Rouse Sport oeuvre is impressive indeed. It has clearly been lightly used for its age and presents very well throughout. The cabin is a highlight with sublime soft leather and Rouse Sport touches in abundance. The original, highly impressive mechanical specification has been further enhanced with a raft of well chosen upgrades, too. This car’s fast Ford credentials are hard to ignore, and we commend it to you.  

Viewing is strongly encouraged, and this lot is located with the vendor in Levenshulme, Manchester. Viewings are STRICTLY BY APPOINTMENT, to make a booking, please use the ‘Enquire About This Vehicle’ button on the listing. Feel free to ask any questions, or try our ‘Frequently Asked Questions’.