German citizens seeking a driving license are required to undergo rigorous training and pass tough driving tests before they are granted that privilege. Once certified, they’re considered fully competent to deal with the unique driving conditions the country offers.

Germany is filled with numerous small hamlets with radar-enforced speed limits of around 35 km/h (21 mph). These villages are typically located just a short distance from the roads that form the famous autobahn system (full name: Bundesautobahn, or “federal expressway”). These highways crisscross the country and range in size from two to six lanes in each direction. Depending on conditions, speed limits run from 80 to 110 km/h (49-68 mph).

Certain areas do offer unrestricted speed zones, which are indicated by a round sign featuring five hash marks. German drivers are taught to never enter the left lane here, except when passing, and to use the turn signal to indicate their intentions to drivers behind them. While in the left lane, it is critical that drivers keep their eyes on the rearview mirror to monitor any fast-approaching cars, then move to the right as quickly as possible. (By law trucks must always stay in the right lane; they’re also speed limited to either 80 or 90 km/h [49 or 55 mph].)

German motorists tend to be very car conscious, and know the informal pecking order governing which autobahn lane their car should travel in. Corvettes are a rare sight in Germany, but even the standard C6 is a pleasant and capable autobahn car. The ultimate autobahn Vette is, of course, the ZR1, since it has the power and the brakes to match most anything it encounters on these unlimited sections of highway.

Outside the realm of factory performance machines, there is a coterie of dedicated German car and motorcycle enthusiasts who spend a lot of euros on maximizing their vehicles’ performance. Among them is Heinz Mueller, a goalie for a major German soccer team and a lover of fast sports cars. In his free time, he attends tuner events at German racetracks, and he enjoys driving his numerous performance cars on the autobahn as well.

In 2010 Mueller commissioned the crew at Callaway Competition in Leingarten to modify his stock Z06 into a road-and-track monster, and he provided a supporting budget commensurate with his goal. The car you see in this story is the result of their efforts.

Project manager Herbie Schuerg did most of the construction, starting by stripping the car down to its bare frame. Incredibly, the interior components alone weighed in at a little over 500 pounds. The resulting parts were catalogued, sold, or stored until they were needed for reassembly.

The frame was sent to Callaway Competition’s rollcage installer, who fitted it with an FIA-approved GT4 ’cage that was then finished in gray. The body, meanwhile, was painted white, and the roof received a clearcoated carbon-fiber panel.

More carbon may be found in the front splitter, rocker panels, and ventilated hood, which cut weight while improving downforce. Out back, a GT4-style wing with a unique hinged mount keeps the rear firmly planted at speed.

Inside, the dash was fitted with suede cloth to minimize glare and then reinstalled around the ’cage. In a nod to Callaway Competition’s GT-class Corvette race cars, a Sparco removable racing steering wheel and a tinted Lexan rear hatch were bolted up in place of their factory counterparts. FIA-approved Recaro Pole Position racing seats supplanted the stock buckets, and the finished cabin was left devoid of both carpeting and sound-deadening material.

Since the car was destined for road-course use, the suspension was fitted with coilover springs featuring competition-spec Bilstein shocks. They work in concert with 50mm front and 40mm rear “sword-type” adjustable sway bars to keep the Vette flat in corners. AP Racing brakes on the front and rear provide ample stopping power.

A Racelogic data-acquisition and video-recording system was mounted inside the car. The setup uses a trio of cameras -- for the front, rear, and driver -- to record all of the action for post-race review.

Under the hood resides a GT3-spec LS7 built by APP Racing Engines. Unencumbered by intake restrictors, it generates 620 hp and 580 lb-ft of torque. It’s allied with a ZR1-spec transmission and differential, the latter fitted with gears that range in ratio from 3.42 to 3.90:1, depending on the owner’s requirements. Long-tube headers routed underneath the car spill into a custom Callaway Competition muffler that terminates in one of the company’s signature “Double D” exhaust tips. The Leingarten gang named the finished project the “Z06RR” (“Road/Race”).

Mueller was delighted with the result, and he quickly learned how to extract maximum performance from the race-spec Corvette. After a short break-in period, he set the fastest time for sports cars at the 2011 Sport Auto tuner event, held at Germany’s Hockenheim circuit. (Check out Mueller’s run on YouTube.)

We had a chance to ride along to Hockenheim in the RR with builder Schuerg. Our route encompassed both rural roads and sections of unlimited autobahn, allowing us to experience the car’s amazing performance in a variety of settings. We even cruised at 140-plus mph in the rain, a setting in which the car proved utterly stable without exhibiting any bad manners. (Helpful hint: At this speed, windshield wipers typically are not required.)

We also witnessed firsthand that autobahn drivers do indeed keep the left lane clear for faster traffic. It’s a good thing, too, as the Z06RR doesn’t appear to be slowing down for anyone.

For more information on Callaway Competition, check out