this engine installed are distinguishable by their twin tailpipes. The V6 is only available on Arc, SE, and Griffin models. In 2004, the V6 engine was replaced by a high pressure turbo straight-4 engine producing . By 2006 this engine was producing even in the non-Aero or non-sport models (US models). The B2x5 engines can suffer from oil pickup issues caused by 'oil sludge' in the lubrication circuit. In 1999, Saab issued a Workshop Bulletin around this issue. The 'sludge' issue primarily affected earlier models between 1999 and 2003, and from 2004 a revised engine positive crankcase ventilation system (PCV) and the use of fully synthetic oil were introduced. Saab created retrofit kits for the earlier 1999–2003 cars as the PCV design differs from the 2004 and later system. In 2005, Saab extended the warranty on the B2x5 engine to eight years and unlimited miles from new for original owners, provided the owner could produce proof that they had followed the manufacturer's oil change intervals. Saab recommended the use of fully synthetic or synthetic-blend oil as a preventative measure. Engine choices Transmissions The 9-5 is available with an Aisin AW 4-speed (50-42LE) automatic transmission Saab reference FA47; from 1997 until 2001, when a new Aisin AW unit replaced the dated four-speed automatic with a five-speed automatic. A five-speed manual transmission is fitted as standard to the base models and the Aero. Six-speed manual transmission was not offered in first-generation 9-5s. Alternative propulsion E85 In 2005, an updated version of the 2.0 L turbocharged I4 was introduced in the European market together with the 2006 9–5. The engine was sold as 2.0t BioPower, optimized to run on E85 producing 132 kW (180 hp) at 5500 rpm. There was also a 2.3T BioPower version sold from 2007. It was also introduced in Australia. E100 In 2007, Saab presented a 9-5 E100 Concept, based on the turbo 2.0. Offering a claimed and 295 lb-ft (400 Nm) of torque, the Concept included the use of increased boost pressure and compression ratio. Safety The 9-5 introduced Saab's Active Head Restraints (SAHR), which moved up and forward to prevent whiplash when the car was struck from the rear. This feature won technology and safety awards in Australia, Denmark, and the United Kingdom. The Saab 9-5 also was one of the first cars to have extensive side-crash protection. The front seats featured torso airbags and head airbags