BMW has revealed a range of optional performance accessories enabling buyers to tweak any six-cylinder 1-series to a specification approaching that of its arresting Tii concept car.To be made public at the Geneva motor show on March 4, the new line of accessories comes in response to increased demand for greater individualisation of the 1-series at dealer level says BMW, which will also be offering a similar line of parts for the larger 3-series from early April. Embracing the engine, suspension, brakes, body and interior, the latest performance accessories have been developed wholly in-house and tested to the same demanding standards BMW applies to all its standard production cars. Although detailed information won’t be issued until the Geneva motor show, Autocar can confirm the options will include a deeper front spoiler with larger cooling ducts and an altered kidney grille. Reworked sills and lightweight carbon fibre door mirrors and a rear spoiler (for the 1-series coupe only) completes the look. BMW will also be offering a range of new graphics packages, including a look that harks back to the Tii concept. Inside, buyers get to choose new sports seats and a trick new steering wheel complete with LED display providing oil and water temperatures, lateral acceleration, optimal shift points for the gearbox and the time. The upgrades available for the suspension include a carbon fibre strut tower brace for added stiffness, retuned springs and the choice of either 18- or 19-inch wheels shod with 215/40 profile tyres. At the same time, BMW is offering upgraded brakes with six pot callipers finished in yellow up front. Engine modifications are slight and involve subtle changes to the inlet manifold and exhaust.Available on all six-cylinder models, BMW doesn’t claim any major improvement in power but says the changes bring added response and a more aggressive engine sound. To be sold through BMW dealers, service partners and retail outlets, each accessory will come with an as yet unspecified warranty.