Not be left behind by its bigger and smaller models the S4 is now available from leading independent Audi Specialists APS of Brackley with a series of enhancement packages. The North American performance house STaSIS Engineering has produced a Signature Series Audi S4. With its Unique blend of cohesive power train and dynamic suspension setup the Audi S4 signature series tops its class in terms of performance. STaSIS has also upgraded the brakes to give the S4 phenomenal stopping power. STaSIS have taken the 2010 onwards model of the S4 and developed the supercharged 3.0 litre V6 to improve its BHP rating from 333bhp to a staggering 410bhp. The STaSIS Signature Audi S4 is now available from APS of Brackley in two model versions the Touring Edition and The Challenge Edition. According to Audi car dealers in Colchester the Touring Edition combines the significant power and torque increase with aggressive suspension and bespoke wheels to Audi's signature sports saloon to deliver additional poise and grace. The Challenge Edition takes the Touring Edition and improves on it by adding racing technology that has been translated for the road. Everything STaSIS's engineers have learned at the racetrack has been distilled into an Audi S4 upgrade package that's also been specified to be civilised for town driving. Features of the S4 Touring Edition: Exhaust - Quad outlet with tunable low RPM resonators Engine - Engine Tuning Software - performance increases to 410 bhp / 370 lb.ft Suspension - 1 inch lower, Increased spring rate, anti-roll bar kit and matched bushings & bump stops Brakes - Optional high-performance street pads and braided stainless steel lines Wheels - 20 inch x 8.5 inch lightweight cast aluminium wheels, Optional 19 inch x 9 inch lightweight cast aluminium wheels Tyres - High performance Features of the S4 Challenge Edition: Exhaust - Quad outlet with tunable high RPM resonators (recommended for manual transmission) Engine - Engine Tuning Software - performance increases to 410 bhp / 370 lb.ft Suspension - Ohlins SL dampers, increased spring rate and high performance anti-roll bar kit Brakes - 6-piston Alcon monobloc calipers, 370 mm 2-piece discs (390-mm optional), stainless steel brake lines & high-performance pads Differential - high-bias centre differential (manual transmission only) Wheels - 20 inch x 9.5 inch ultra-lightweight forged aluminium wheels Tyres - extreme performance