The German tuning engineers from AC Schnitzer got their hands on the convertible version Mini Cooper S and developed a series of accessories and technical elements that give it a more unique appearance while improving its performance.  
The AC Schnitzer Mini Cooper S Convertible is powered by a 1.6-litre engine that has been upgraded from 175 hp developed by the stock version, to 208 hp (153 kW) with an "export version" outputting 226 hp (166 kW) also available. To accommodate the power increase the AC Schnitzer Mini Cooper S Convertible has been fitted with sports susepension  that includes a spring kit and offers the possibility to adjusts its height and the company’s custom limited slip differential for excellent adhesion.
As for exterior mods the AC Schnitzer Mini Cooper S Convertible features a new front spoiler, a set of decals available in either black, white or chrome, a rear silencer and a set of 17 inch or optional 18 inch custom rims.
Inside the AC Schnitzer Mini Cooper S Convertible received velour floor mats and aluminium pedals, foot rests, handbrake handle and gear knob.
AC Schnitzer press release :
"MINI Look" by AC Schnitzer
With innovative developments, the Aachen-based tuning specialist creates driving pleasure and the perfect MINI Look
With its new Convertible (R57), MINI has now produced the next body variant of the cult car. The AC Schnitzer designers and engineers have already developed a range of special accessories for the new MINI. In keeping with the history of the MINI, the Aachen-based tuning specialists have concentrated on developments in the field of performance upgrades, sports rear silencer, sports suspension, alloy wheels, exterior components and interior details.
Under the small bonnet of the MINI Cooper S the 1.6 litre engine provides power of 175 HP. The AC Schnitzer performance upgrade energizes the MINI Cooper S to 153 kW/208 HP. Under the same conditions, the uprated export version of the Cooper S takes the standard power of 128 kW/175 HP to an impressive 166 kW/226 HP. At the same time, the AC Schnitzer limited slip differential in the MINI Cooper S and Special Model JCW (John Cooper Works) guarantees maximum driving pleasure with excellent ground adhesion.
The perfect driving experience is complemented by the acoustic qualities of the AC Schnitzer sports silencer in special steel with chromed Racing tailpipe for the MINI Cooper S and JCW. The AC Schnitzer sports exhaust perfectly adapts the complete exhaust system to the needs of
high performance and tuned engines.
An equally important contribution to driving performance is provided by the renowned AC Schnitzer suspension components, available in the form of suspension spring kit and height-adjustable racing suspension. In conjunction with an aluminium strut brace for the front, even more performance can be extracted from the MINI One, Cooper or Cooper S.
To fill the wheelarches of the new MINI, AC Schnitzer is also offering a choice of several wheel and tyre combinations with Mi1 rims in 17" and Mi2 rims in 18".
Visually, the new series MINI shows few differences from the current series. The designers of AC Schnitzer have changed this with front spoilers and rear skirts (for the MINI Cooper S), which not only enhance the looks of the MINI but also offer aerodynamic advantages. Decal sets in white, black or chrome/black put the finishing touches to the appearance of all MINIs.
Characteristic of the MINI, in the interior the central instruments are arranged between driver and passenger. Characteristic of AC Schnitzer, sporting elements are applied to the driver’s workplace. So the Aachen designers offer gear knobs, handbrake handle, pedals and foot rests in aluminium, with velours floor mats.

Source: AC Schnitzer