The Mégane R23.R is based on the Mégane Renault Sport 230 F1 Team R26, but is 123 kg (271 lb) lighter. Weight reduction is achieved via the removal of the rear seats and seat belts, passenger airbag and curtain airbags (the driver's airbag remains), climate control (air conditioning remains as standard), rear wash/wipe and heated rear window, front fog lamps, headlamp washers, radio/CD player and most of the soundproofing.
Other features include a carbon fibre bonnet, polycarbonate tailgate and rear side windows, Sabelt seats with carbon fibre shell and aluminium base, 6-point harnesses, a rear spoiler, optional roll cage and an optional titanium exhaust.
New parts include new front springs (14 mm/100 kg), new rear springs (16.2 mm/100 kg), recalibrated shock absorber settings, grooved brake discs, new alloy wheels are fitted with a different offset increasing the track by 4 mm (0.2 in), optional Toyo Proxes R888 225/40R18 tyres (Michelin Pilot Sport 2 235/40R18 standard) and stiffer lower arm bushes.
450 vehicles were made with 230 destined for the UK market. The car went on sale in October 2008 for £22,990. The car was unveiled at The 2008 British International Motor Show.
Source: Wikipedia (original)