In the December 2008 issue, we shake down the three compact German musclecars of the day - BMW M3, Mercedes-Benz C63 AMG, Audi RS4. For current or aspiring owners, this buyers guide showcases the latest performance upgrades for all three platforms. Compiled by Anthony Gelinas
Active Autowerke has created engine management upgrades based on various tuning options available for the new M3. While the software recalibrations vary based on other modifications, the basic tuning principals are still the same. AA software has been programmed to remap the DME tables, recalibrate throttle response, and optimize ignition timing and fuel delivery. Contact for pricing.
Every shifted gear interrupts drivetrain momentum, so anything you can do to make those transitions as smooth and quick as possible can reduce zero-to-60 and quarter-mile times. This Active Autowerke short shifter kit is engineered as a direct replacement for the factory assembly and requires no modifications to install. It is said to reduce the distance between shifts by a claimed 30 percent. To further enhance feel, an optional weighted (8.25 ounces vs. the stock 3.25) signature Active Autowerke knob, with included leather boot, is available. $475
At first glance, the Eisenmann rear muffler section for the E92 looks like a factory-installed piece. Manufactured in Germany from 304 stainless steel, this assembly utilizes two muffler sections joined together by a twin bypass system designed to equalize pressure and optimize flow. Depending on your needs or tolerance for sound, it is available in sport and race versions. $2,839
Swapping the stock pulleys for lightweight versions reduces rotational mass and decreases parasitic drag on your engine. Evosport has developed a Power Pulley system for the S65 V8 equipped with a six-speed manual transmission. The kit replaces the crankshaft pulley with a black anodized, T-6061 billet aluminum unit and includes a replacement belt and new crankshaft bolts - helpful, since these bolts can be difficult to remove. $395
There's no denying the E92 M3 is more at home on a road course than the quarter mile. That's not so say it doesn't have good power, but there's more to be had, so it was only a matter of time before a forced induction system found its way under the hood. Supercharging has traditionally been the most successful way to tap the hidden power in BMW engines, and G-power offers its EVO-SK compressor systems in three different trim levels with output ranging from 525-635 hp. Contact for pricing.
Far beyond a simple filter and bracket combo, GruppeM's S65 intake is a completely reengineered intake system. One unique feature is that it takes advantage of three inlets for air to be drawn into the airbox assembly via a carbon-fiber front bumper scoop, an extension into the hood scoop, and the two kidney grille inlets. The main benefit comes at high on-road speeds when air is naturally pressurized around these three areas. $2,456.23
Milltek's cat-back exhaust is manufactured from anti-magnetic, type-304, aircraft-grade stainless steel for great durability. This material also allows it to be less susceptible to discoloration. The system features full-flow, mandrel-bent piping and high-flow real silencers, each with twin 3.5-inch tailpipes. With the completion of the cat-back portion, development has begun on the next big restriction, the factory downpipes. Contact for pricing.
Mercedes-Benz C63 AMG
The location and configuration of the factory airbox assemblies within the AMG engine bay created a unique challenge for the engineers at Carbonio. They had to figure out a way to satisfy the air demands of the 6.2-liter V8, and the answer was a pair of airbox assemblies with greater internal volume, flow optimized shape and internal high-flow filters. The autoclave pre-preg carbon-fiber construction gives the kit a factory look without the factory flow limitations. $1,950
Evosport has developed its Evo2 software and a race header system for the C63's already impressive V8. The mandrel-bent, T304 stainless, long-tube headers are hand-crafted and feature a tri-Y modular design with large primaries and precision TIG welds for optimal flow and durability. In addition to being optimized for the headers, Evo2 proprietary software is programmed to improve throttle response, recalibrate ignition timing and eliminate that pesky top-speed governor. Contact for pricing.
Developed using variable active damping technology, Evosport's C63 crankshaft pulley is designed to reduce rotational mass for increased power while offering the same vibration resistance inherent in the stock design. The pulley itself is cut from high-grade T-6061 aluminum then fully anodized black for durability and a stealthy install. $1,995
Renntech stainless-steel headers are designed as direct replacements for the factory log-style exhaust manifolds and require no additional modifications to fit. Unlike the log manifolds, where each cylinder dumps into one bottlenecked common area before its gases are forced out, Renntech headers have been designed to give each cylinder its own path, effectively reducing backpressure while increasing power and mid-range throttle response. $4,995
If you browse the list of Mercedes vehicles equipped with the 6.2-liter AMG V8 you'll notice their power and torque level vary according to model. Each application has been electronically manipulated based on the target vehicle. Renntech offers two ways to uncork the C63's 6.2-liter V8 and realize its full potential. Upgrade 1 bumps power to 476 hp and 460 lb-ft of torque. Upgrade 2 takes the de-restriction further with more aggressive throttle mapping and pushing output to 501 hp and 475 lb-ft. Along with additional power, top speed can be increased from 155 to 187 mph.
Upgrade 1: $2,495; Upgrade 2: $3,495
VRP's VR530 Power Package for the C63 is comprised of four main parts. The 10-percent larger diameter alternator and water pump pullies are machined from T6061 billet aluminum to reduce parasitic drag, increasing throttle response and reducing drivetrain loss. The low-restriction air filters help keep the air supply up. Phenolic spacers help keep intake temperatures down by reducing the amount of heat transferred from the cylinder heads into the intake manifold. To take advantage of the reduced intake temperatures, an extension harness relocates the intake air temperature sensor from the firewall to further up front by the driver's side fog light. $749
Again, GruppeM has taken intake development to an entirely different level. Going well beyond the simplistic ?filter on a stick? concept, GruppeM reengineered the RS4?s intake into a fully sealed system that draws pressurized air directly from the grille?like a stock airbox, but with larger volume. Air enters through a specially designed cone filter and is then fed directly into the engine. Carbon fiber construction matches the RS4?s factory engine covers and a red silicone coupler matches the valve covers for a faithful factory look. $1,264.77
Milltek has designed a pair of sport downpipes to complement its cat-back exhaust system. These pipes replace the four extremely restrictive stock catalytic convertors (two pre-cats and two catalysts) found in the OEM exhaust system. The 63.5mm (2.5-inch) sport downpipes feature precision-cut flanges, heavy-duty flex joints and mounting brackets. Milltek employs HJS 200 CPSI (Cells Per Square Inch) catalytic converters for maximum flow and reliability. $2,199
One of the RS4's coolest features is its ability to change its exhaust tone with simple push of a button. Milltek has developed a versatile stainless-steel cat-back exhaust that gives customers the choice of maintaining this feature or deleting it. The key feature of the dual 63.5mm (2.5-inch) system is the front H-pipe designed to allow excess pressure from one side of the exhaust to bleed over to the other in order to maximize flow throughout the entire powerband. The 160mm-wide oval tips are available in either a polished or special 'thermoset' black powdercoat finish. $1,699-$2,999
MTM's 530-hp supercharger kit effectively gives the RS4 the kind of horsepower some feel it should have had the day it left the factory. Not that 420 hp is anything to sniff at, but expectations are understandably high for the RS model line. The best feature of this kit, besides the increase in power, is its superior build quality and factory appearance. If not for the MTM logo, one look at the intake manifold would have you convinced it was OEM-issue. $49,980
It seems that no matter how good a car performs from the factory, manufacturers always leave room for improvement. While the modest 10-20 hp gains (based on fuel octane levels) seem hardly worth the expense when compared to a turbocharged engine, the benefits from optimized ignition timing, a recalibrated electronic gas pedal, increased rev limiter and removal of the top-speed governor are worth every penny. Neuspeed's Power Pack includes a K&N high-flow air filter and new software for both of the RS4's MED9 engine control units. $744.95