German tuner G Power are using technology from their record braking 800 HP M5 Hurricane RR on a smaller scale on and applied it to the BMW Z4 3.0i. They are offering performance upgrades that increase output figures on the G POWER BMW Z4 3.0i to a total of 286 HP (210 kW) @ 6,000 rpm and 345 Nm of torque @ 3,500 rpm, which means a 55 HP and 45 Nm of torque increase over the stock version.
These new figures enable the G POWER BMW Z4 3.0i to sprint from 0 to 100 Km/h in 5.4 seconds and the modifications consists of a new, perfected SK Plus ‘Sporty Drive’ supercharger system built from scratch and a hand built rear sport silencer made from stainless steel.
The G POWER BMW Z4 3.0i is also offered with coil-over suspension with 9-way adjustable compression and rebound and a set of 20 inch alloy wheels wrapped in Michelin tyres.
The tuner says they can apply the same treatment on the BMW 3 Series E46 and in both cases pricing starts at 2,500 Euro. 
G-Power press release :
World premiere – G-POWER presents the technology featured in the world’s fastest saloon car starting at only EUR 2,500.00.
Technology transfer by G-POWER – the technology from the 800 hp world record-breaking G-POWER M5 HURRICANE RR is now also available for the BMW Z4 E85 and 3 Series E46, delivering a power increase of up to 55 hp.
G-POWER Z4 3.0i with SK Plus “Sporty Drive” supercharger system
• 210 kW/286 hp @ 6,000 rpm (+ 55 hp/40 kW)
• 345 Nm @ 3,500 rpm (+ 45 Nm)
• 0-100 km/h: 5.4s
The G-POWER SK Plus supercharger system has proven its worth in more than 1000 vehicles, and now a redeveloped version of the technology featured in the world’s fastest saloon car with a top speed of 372 km/h has found its way under the bonnet of the BMW Z4 E85 and the BMW 3 Series E46.
Following a 12-month development program, involving extensive CAD work complemented with virtual computational fluid dynamics analysis (CFD analysis) and intensive test driving, G-POWER presents the all-new, perfected SK Plus “Sporty Drive” supercharger system. All components have been developed from scratch or extensively revised based on our many years of experience. The resulting components are manufactured using state-of-the-art production processes. The supercharger mounting plate and the complete air ducting, for example, are made from lightweight cast aluminium. Plus, all parts of the SK Plus “Sporty Drive” system made from sheet metal are CNC laser cut from non-corroding materials. Due to our investment in sophisticated tooling and equipment, as well as our high-volume manufacturing setup, we are able to offer consistent quality at a considerably lower price.
Moreover, thanks to the complete redevelopment of the system, its overall part count has been reduced, further simplifying the installation of the SK Plus “Sporty Drive” system. An optimized storage facility means that the availability of the system has been improved, facilitating dispatch usually within 1-2 days after receipt of order.
Like its “big brother” the G-POWER M5 HURRICANE RR, the heart of the system is an OE-quality supercharger from renowned German manufacturer ASA Kompressor GmbH. The all-new ASA T3-313 replaces the previous ASA TM3 supercharger. Optimization of the geometry of the compressor and its housing, originally developed for the record-breaking vehicle, enable earlier and even more efficient build-up of boost pressure, thus ensuring outstanding pulling power in the middle of the rev range. At full revs, the G-POWER SK Plus supercharger system achieves an increase in output of up to 55 hp compared with the series-production version, at a relative boost pressure of only 0.3 bar. Fitted to the 3.0l engine in the BMW Z4 3.0i or the BMW E46 330i, maximum output climbs to ca. 210 kW/286 hp and 345 Nm of torque.
More important to the customer than the naked figures, however, is the power delivery – i.e. the experience generated by this additional output. The key here is the term “Sporty Drive”. In the specification for every tuning program undertaken by G-POWER, this aspect is afforded the same priority as the target power increase itself.
The very first thing you notice behind the wheel of a BMW Z4 E85 or a BMW 3 Series E46 with a G-POWER SK Plus supercharger system is the extremely sporty throttle response. Every input from the gas pedal is translated immediately into forward propulsion, without the lag usually associated even with modern turbocharged engines. The driver’s command is proportionally and instantaneously implemented. One further characteristic of mechanical supercharging using the ASA radial supercharger is the outstanding torque in the middle of the rev range, which is particularly impressive during overtaking manoeuvres. This lively response from mid-range revs increases continuously until engine speed peaks, which is also where maximum boost pressure is achieved. The acceleration experience is akin to being fired from a catapult.
In order to ensure that all this extra power is delivered safely to the road, G-POWER recommends a combination of the G-POWER 20-inch SILVERSTONE DIAMOND wheel set with Michelin tyres measuring 245/30 ZR 20 on the front and 285/25 ZR 20 on the rear and the G-POWER “GZ4-RS” coil-over suspension with 9-way adjustable compression and rebound. The outcome is higher cornering speeds and improved directional stability at top speed.
Always worthy of consideration is the G-POWER rear sport silencer. This hand-built silencer is made completely inside and out from stainless steel and combines an outstanding fit with OE quality. As fine as they may be, however, these qualities pale to insignificance with the first chords of the symphony flowing from the 4 x 76 mm tail pipes. With a powerful bass starting at low engine speed, turning up the heat as it rises through the middle and upper rev ranges, the G-POWER rear silencer skilfully underscores the significantly increased sporty character of any BMW tuned by G-POWER. This characteristic sound is made possible by G-POWER’s patented “DEEPTONE” technology.
The last question is, of course, the critical one – How much does it all cost? Entry into the world of G-POWER supercharger systems starts at EUR 2,500.00 (net) for the installation-ready SK Plus supercharger system. A TÜV certificate of conformity makes TÜV registration straightforward. If preferred, complete installation including TÜV inspection can also be carried out by G-POWER at its headquarters in Autenzell.

Source: G-Power