Toyota's technical chief Pascal Vasselon says the new TF108 is a departure from recent cars from the Japanese squad.
The Cologne-based outfit endured a disappointing 2007 season, scoring just 13 points on their way to sixth place in the standings.
Last year's TF107 failed to be competitive enough throughout the season, making Toyota change their design philosophy for the new TF108.
"The aerodynamic concept of this car has changed," said Vasselon. "The TF107 was an evolution of the TF106 but this time the new package is a departure from recent Toyotas.
"The primary aerodynamic design philosophy for the TF108 is geared towards optimising the entire package to minimise balance and downforce changes throughout a lap, thereby producing a more driveable, aerodynamically robust car.
"In addition to the aerodynamic philosophy, another fundamental change is the wheelbase, which is longer.
"In mechanical terms we felt we had a strong basis in the TF107's characteristics so we have focused on making a few refinements. We have made refinements to improve the weight over stiffness ratio with better structural efficiency, so we achieve the same stiffness values with less weight."
Vasselon says wind tunnel testing has showed the car is on target, and the Frenchman admits he is very excited about the new machine.
"I am pleased to say the TF108 is on target, the aerodynamic efficiency and associated performance metrics continue to improve rapidly, but of course the real test will come when it runs on the track," he added.
"The TF108 looks great and we are very excited to see it in action to learn if it lives up to our high expectations."
He also said it would be unrealistic to expect Toyota to fight for the title this year, and he is targeting podium finishes often instead.
"Personally, I believe the target should be to fight systematically for the podium in 2008. Next year we should aim to achieve what BMW Sauber achieved in 2007, which was to be the best of the rest.
"It would not be realistic to talk of fighting for the title this year but we want significant improvement."