Rosberg committed to Williams future

The German is at the centre of speculation about his future, with rumours linking him with a move to Toyota as replacement for Ralf Schumacher if the Japanese team decide not to retain the veteran.

But although Rosberg says he is flattered by the talk, he has made it clear to Toyota that he is not interested in joining them.

And his views have become entrenched after he recently saw the design plans for Williams' 2008 contender, the FW30.

"The switch to Toyota is out of question since I have a solid Williams contract for next year," said Rosberg. "I am happy at Williams. And it looks like we will make a substantial step forward in 2008.

"I reckon that we might be able to make up one or two places in the constructors' championship, which means that we would leave Renault behind us.

"I expect that we can reach BMW-Sauber and we should be able to become the third force in Formula One. The step will be at least as big as it was from last year to this one. And that was big already."

Rosberg feels his development as a driver has come on greatly this year and feels that his level of input to development is on a par with more experienced teammate Alex Wurz.

"I definitely feel that I don't need to hide from Alex in that area, especially in everything that is track-based," he said.

"I think I'm very good in that area and I've been on it most of the year on that. I have even pushed set-up directions myself that Alex has followed me with, which have really helped the performance of the car. So I think I am coming along pretty well.

"Of course, I still have to improve a lot even there, and I'm sure I can do a lot and am trying to do. The other place where you can probably with experience become stronger and stronger is more the general things, helping them, say with building the new car.

"And also in giving them stronger opinions on which way they should go on certain big aspects on it. I'm already starting to have influence there now and I'm sure with experience you can get stronger and stronger there and I think it's an important area."

Rosberg's form this year has not only seen him linked with the Toyota team, as there have even been suggestions that he is in the frame for a McLaren switch if the team lose Fernando Alonso.

When asked by autosport.com about his reaction to the McLaren speculation, he said: "I smile, because it's always fun for a young driver to be talked about.

"I have a contract with Williams for next year, and I don't want to talk about the rumours any further. It's best not to go into any of that."