Michael: Wurz stands out from rivals

"In terms of real tangible benefit to the team, Alex is the best guy I've ever worked with," technical director Sam Michael told reporters ahead of the season-opening Australian Grand Prix on Thursday.

"And I'm not just saying that. Even if he wasn't racing for us this year and he had decided to go somewhere else, I would still say that.

"I would say there's no fewer than two or three designs on the Williams car now that came from Alex that actually make the car go faster. They are things that if you took them off we would go a 10th (of a second) slower," he added.

"I don't know any other driver like that. I've never worked with another driver where I can turn around and say there's a design or there's a change that we made and it's because of that bloke there.

"There's some guys that I know that even if they drove around in Formula One cars for 10 years, still wouldn't be able to say the things that Alex has said."

The Austrian arrived at Williams last season after five years as a McLaren test driver and secured a race seat for 2007 following the departure of Australian Mark Webber to Red Bull.

Sunday's race at Albert Park will be the driver's first Australian Grand Prix appearance since 2000, when he drove for Benetton.

In the six subsequent seasons, the 33-year-old has raced just once - taking third place at the 2005 San Marino Grand Prix as a stand-in for McLaren's injured Colombian Juan Pablo Montoya.

"I haven't been away on holiday for six years, I've been driving in world championship-winning teams, compared myself in long runs and short runs to world champions, race winners, future talents and that raises your level," he told a news conference.

"And also I'm mature, so I hope I'm a much stronger guy than I was then."