Stuttgart. Porsche is celebrating the 25th birthday of its roadster family with a special anniversary model: the Boxster 25 Years. The limited edition is restricted to 1,250 units worldwide and is based on the GTS 4.0 model, which is powered by a 4.0-litre six-cylinder boxer engine with 294 kW (400 PS). It makes reference to numerous design features of the Boxster concept car that heralded the success story of the open-top two-seater at the 1993 Detroit Motor Show. The production version was launched in 1996 with hardly any changes in its visual appearance and is now in its fourth generation.