Porsche occupies the north-west of the city with its headquarters in Zuffenhausen and Mercedes-Benz owns the south-east with its vast holdings in Neckarsulm. Both places serve as religious experiences for the automotive true believers.

Happily, the pilgrims are encouraged to travel between the friendly rivals and both car makers welcome the faithful in the best way they know how - each with a museum to mark their progress and achievements along the timeline that is the relatively short age of the automobile.

So if a museum is the repository of history for a country, district or city, what then can be said by an automotive museum dedicated to a car maker? The short answer is "plenty" and perhaps one of the most interesting observations is of the clientele.

At Porsche, visitors wear bright corporate or motorsport clothing, gather around the various exhibits and babble excitedly about each one.

At Mercedes-Benz, they are older, more subdued and at times almost reverential as they take photographs and talk quietly, pointing out various details of the cars to each other.

Both museum buildings are sculptural works in their own right, the Porsche edifice opened just a couple of years ago in the new Porsche Zentrum complex after being housed in a barn within the factory grounds for many years.

At Mercedes-Benz, the visit starts on the outside where visitors can gaze on a life-size bronze statue of the great Juan Manuel Fangio and his Mercedes-Benz W196 grand prix car.

Inside, after paying at the admission desk and collecting a headset, it is simply a case of taking a lift to the top floor before descending a series of circular ramps to travel through two world wars, the Russian occupation of east Germany and eventual reunification before stopping at the ground floor to marvel at Mercedes-Benz's technological achievements.

Exhibits along the way highlight the very first cars and tell the story of Emile Jellinek and his daughter, Mercedes, who gave her name to the fledgling Benz company after her father helped bankroll it.

Exhibits show the progression from motorised buggies to the first real cars and buses, highlight the grandeur of the 1920s and '30s, the company's motor racing involvement and a dizzying number of prototypes, many used to further the cause of road safety long before anyone else was acknowledging it.

At Porsche, the timeline is a little shorter for the company, but not for the engineering genius named Ferdinand Porsche who was showing off the world's first hybrid car at the Paris World Fair in 1900.

Porsche is a company with motorsport in its DNA and the sparkling museum reflects it. Tiny racing cars dot the place alongside the early prototype and production cars.

Lean far enough into the cockpits of some and the sweet smell of petrol and perspiration is still there, blending keenly with the twin odours of fear and adrenalin.

And there are the oddities. A prototype diesel tractor designed and built by Ferdinand Porsche, the C88 small sedan concept built to give Porsche entry into the Chinese market, the 918 Spider that claimed a Nurburgring Nordschliefe lap record, a 959 aerodynamic study car with notes scribbled on the bodywork in texta pen by the engineers.

There are the famous race cars, the 917/20 "Pink Pig", a Le Mans racer painted to show the various cuts of meat from a pig, Mark Donohue's 917/30 Can-Am racing car with its awesome turbocharged 12-cylinder engine, Jacky Ickx's Le Mans winner and Paris-Dakar Rally-winning car, the 1969 Bergspyder hillclimb car used to good effect by Rolf Stommelen and Dan Gurney's French Grand prix-winning 804, the only Porsche ever to win a modern grand prix.

At the end of it all? The gift shop.

The faithful always need a souvenir.

■ The Porsche Museum is at Porscheplatz 1, 70435 Stuttgart-Zuffenhausen. Opening hours are 9am-6pm Tuesday to Sunday and adult admission is €8 (about $12). By train take S0-Bahn line S6 and get off at Neuwirtshaus/Porscheplatz station. Email info.museum@porsche.de.

■ The Mercedes-Benz Museum is at Mercedesstrasse 100, 70372 Stuttgart. Opening hours are 9am - 6pm Tuesday to Sunday and adult admission is €8. By train take S-Bahn line S1, get off at Neckar Park station and follow the signs. Email classic@daimler.com.