The hottest version yet of the awe-inspiring rally-bred Subaru Impreza WRX STi has been unleashed in South Africa.

The hottest version yet of the awe-inspiring rally-bred Subaru Impreza WRX STi has been unleashed in South Africa.

Subaru SA has 15 hand-prepared versions of the fastest production Subaru available in this country, the special edition Impreza WRX STi, to give otherwise ordinary drivers a greater taste of its rally-bred capabilities.

Based on the standard model, the limited-edition STimulating STi uses the horizontally opposed 2,0-litre turbocharged engine used in the WRX STi.

With its hollow intake and sodium-filled exhaust valves, inertia and friction are reduced for high-revving reliability and smoothness. Coupled with lightweight valve lifters and Subaru's variable valve timing system, they help to make the engine more responsive over the widest rev range.

Changes to the STi engine include a Prodrive performance exhaust system and an engine ECM software upgrade. In standard trim, the STi develops 195 kW at 6 000 r/min and 343 N.m of torque at 4 000 r/min.

The standard STi's power peak is available in the STimulating STi between 5 000 and 6 500 r/min and the standard maximum torque peak is available from just below 3 500 r/min all the way to 5 750 r/min making the car much more driveable.

In independent performance testing, the STi sprinted to 100km/h from a standing start in 5,02 seconds. The quarter mile was covered in 13,3 seconds while the standing kilometre was handled in 24,67 seconds at a terminal speed of 208,5km/h.

With the car using Subaru's renowned All-Wheel Drive system, the WRX STi's suspension has been uprated to improve stability and control geometry changes in hard cornering. A stiffening support arm has been added to suppress movement in the front cross member, minimising changes while performing sudden manoeuvres.

The layout of the rear suspension top mount has been changed too not only helping to enhance the feeling of solidity, it also improving steering stability, performance and ride comfort, as well as cutting down noise and vibration from the road.

Because so many of these refinements incorporated as standard on the WRX STi are derived directly from the competition model, driving potential is maximised, and many owners will be able to enjoy the benefits on the track as well.

Changes to the STi include Prodrive springs lowering the car by a further 25mm while the wheel alignment settings have been altered and are set up individually on each car to optimise handling.

Active safety and accident avoidance have been stepped up using Brembo discs with ABS and EBD. Ring-shaped reinforcement frames encircle the driver and passengers to protect them against impact from any direction.

Dual airbags are standard, while seat belts have electronic pretensioners and load limiters in front, with 3-point belts at the rear. ISO-FIX child seat mounts and tether anchors are included.

An impact-reducing type brake pedal has been included too to lessen the possibility of lower limb injury in the event of a frontal collision. Impact-absorbing pedestrian protection is built into the collapsible wipers that reduce the most common cause of head injuries if a pedestrian is thrown up over the front of the car.

Other changes made to the limited edition include tinted windows and specific badging.

Subaru SA is making 15 of these machines available for R395 000, just R13 000 more than the standard STi's retail price of R381 950.