Oxfordshire teams Marussia and Caterham showed off their new cars as testing got under way at the Circuito de Jerez in Spain.
Banbury-based Marussia were first out as they finally stepped on to a more level playing field with their Formula 1 rivals.
Just 45 minutes prior to the start of the first test, they unveiled the MR02 that now boasts KERS (kinetic energy recovery system).
And half-an-hour later, Leafield outfit Caterham rolled out their CT03 with drivers Charles Pic, signed from Marussia, and another rookie in Dutchman Giedo van der Garde.
Caterham pinched tenth place in the constructors’ standings – and with it a considerable sum of money – from Marussia in the final race of last season in Brazil when Vitaly Petrov claimed 11th spot at Interlagos.
The Banbury marque are convinced the lack of KERS cost them dear.
But with the device now on the car, team principal John Booth has no doubt a more robust challenge is on the cards, despite his rookie line-up.
Briton Max Chilton has already secured one seat and Brazilian Luiz Razia is expected to be confirmed soon.
Booth said: “We embark on the first pre-season test of 2013 feeling very positive about our new car.
“It was said many times during 2012 the lack of KERS was the defining factor in determining our championship position.
“KERS was a strategic omission from our package until now. We opted to place the emphasis on aerodynamics.
“Our trackside engineering team has spent the winter preparing for the addition of KERS to ensure we can hit the ground running with effect from this week, and use the short period of testing we have to get the car optimised for Melbourne.”
Caterham, like Marussia, are yet to score a point in the three years have been competing in F1.
Despite that, team principal Cyril Abiteboul, ahead of his first full campaign in charge, said: “This is the first car we have produced since I joined the team, so this is a proud day for me.
“Driving the cars this year are Charles and Giedo, two drivers who give us a good mix of youth and experience inside and outside Formula 1.
“They are both young and dynamic, and we expect their enthusiasm for the sport and the team will be fuelling our growth.”