"The car is a good general package," Spengler said. "There are manufacturers that are very good on some tracks then struggle on others, but we have been more or less pretty good on every track, and that's what made us strong last year."

Spengler said that this season a few improvements on the car are allowed but permitted modifications are very limited.

The rules make for evenly matched cars, so the DTM is seen by the motoring world as a really difficult championship to win - even harder than the Formula 1.

"As soon as you have something that is not 100 percent perfect, you can't win," Spengler said. "You need to have a perfect car all the time for any kind of condition and you need to drive perfectly with no mistakes at all."

Last year's champion said he expects a "tough season" ahead because opponents view his team as very strong and worked very hard all winter.

"I'm not planning anything, I'm just going to start the season like I did last year," he said.

"My goal is to try and win as many races as possible and then we'll see at the end of the season where we end up in the championship."

In their daily lives, both racing drivers have developed deep affection for BMW cars, especially the high-performance M series.

Spengler said he has been driving an M3 road car and in the winter he drives an X6 M50d. Even so, he said he is always interesting in trying an M car.

"If I am at a dealership and see an M car, I feel like a kid and want to sit in the car, see how it is and try it," he said, "Definitely, the BMW M is something big for me."

Ravaglia said that in his eyes BMW M is the "embodiment of power, dynamics and really sporty cars" and "the BMW M cars are just beautiful".

He added that the BMW M also features a "unique mix" - "they have the racing DNA, but still you can comfortably use them in everyday life."

Ravaglia said he often drives a M3 or M5, while in winter he prefers the X5.

Xu Xiao contributed to the story.