Feb.29 (GMM) Nick Heidfeld is facing a big challenge to emerge as a grand prix winner in 2008, according to former world champion Keke Rosberg.

The 1982 title winner says that while BMW Sauber's goals are ambitious for 2008, many obstacles are still facing the 30-year-old German as he prepares to start his ninth full season in F1.

"Last season, he (Heidfeld) had Robert Kubica slightly under control, but the Pole was a bit faster throughout the winter," Rosberg, the 59-year-old Finnish father of Heidfeld's countryman Nico Rosberg, told the magazine Sport Bild.

Another hurdle for Heidfeld is the true competitiveness of BMW's new single seater, the radical F1.08, which although promising endured a difficult birth earlier this winter.

"We need to see what the true picture is," Rosberg, to attend all the races in 2008 as a German-language commentator, added.

"BMW have said very clearly that they want not just one but several wins. This is a very high goal.

"The jump into the class of the two top teams is enormous, complicated and expensive, and the question is whether BMW have made it," Rosberg said.

"I know Alonso has spoken very highly of them, so either he wants a contract or, as a driver, he knows more than we do."

Interestingly, Rosberg says the difference between BMW and Williams - his son's employer - this season is the respective "risk" the teams have applied to finding their way to the front of the grid.

"Williams have a more conservative attitude," he pointed out, "while BMW has gone for an extreme solution, which is make or break.

"But I do not know how good the (Williams) car is," he admits. "When I talk to Nico, we talk about other things; he tells me nothing (about F1), even when I push him!"