Gone are many of the winglets and other exterior appendages, so the cars look somewhat sleeker and narrower. The series also will use slick tires, as opposed to grooved ones, for the first time since 1997.
All of which raises the question as to which Formula One drivers will be the fastest when the series begins in Australia.
"Who knows when we get to the first grand prix who's going to be quick," Hamilton told reporters during a visit to the United States in December. "Everyone's going to be in the same boat" in terms of adapting to the changes, he said.
Hamilton, when asked if the changes would make it harder to repeat as champion, replied: "I don't think it's going to make it easier."
And his team manager Ron Dennis said it would be "a very challenging period in the history of motor sports."
For most Formula One drivers, that's an additional burden to the overall challenge of catching Hamilton and Massa on any given day.
Their main pursuers include Massa teammate Kimi Raikkonen, the Finn who won the championship in 2007 and finished third in points last year with two victories, in Malaysia and Spain.
Robert Kubica, who stunned the sport with a victory in Canada last season -- the first win for him, for a Polish driver and for his BMW Sauber team -- is back after finishing fourth in points. His teammate Nick Heidfeld was sixth in the title chase.
Then there's two-time champion Fernando Alonso, who last year returned to Renault from McLaren. He finished the season strong with consecutive wins in Singapore and Japan to place fifth in the standings, but he still ended a distant 37 points behind Hamilton.
But Alonso is optimistic about this year.
"The rule changes are a big opportunity, if we do a good job, to fight for the championship," the Spaniard said in an interview in January. "Everybody is starting from zero and if we do a good job we can be up with them."
And with Honda having left the series, Toyota remains the only Japanese team in Formula One, with drivers Timo Glock and Jarno Trulli.
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james.peltz@latimes.com
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THE FIVE TO WATCH IN 2009
Lewis Hamilton: The British driver made history last year as the youngest Formula One champion, at 23, and he still might be the most formidable driver in the sport. Hamilton had five victories last year for McLaren Mercedes and is the defending winner of this season's opener in Melbourne, Australia.
