BARCELONA, Spain – Williams unveiled its 2013 Formula 1 at the Barcelona circuit in Spain.The last of the 11 teams to show off their new car, Williams hoped the FW35 would be an improvement on the FW34 which Pastor Maldonado drove to the team's first victory in nearly eight years in 2012.Technical director Mike Coughlan said: "Given the rule stability over the winter, I'm pleased with the gains that we've been able to make with this car. It's a better, more refined F1 car than the FW34."‘CHALLENGE THE VERY BEST’Williams is the second most successful team in F1, in terms of Constructors' championships (nine) but finished eighth in 2012. Founder Frank Williams said: "We will have to wait until Australia to truly see what we have,but we believe it is a step forward from 2012's car which was also a very competitive vehicle."Williams has been at the top many times over the last 30 years. It's the nature of the sport to have ups and downs, but when we are down we always fight our way back. I'm hoping that with the current team we have in place... we will be in a position to challenge the very best."Maldonado has a new team mate in 2013 year as rookie Valtteri Bottas, previously a reserve, moves up to take the No.2 spot. Susie Wolff, wife of shareholder and new Mercedes team executive director Toto, is the development driver and was first to drive the new car in a shakedown at the Idiada track in Spain before Maldonado took over for the second pre-season test.Williams said more than 80% of the car was new, including the gearbox, suspension, radiators, floor, exhausts, bodywork and nose. The Renault-powered team said a "considerable" amount of weight had been saved.Reliability work through the northern winter had been promising, with the gearbox alone completing 3200km on the dyno at the factory.Maldonado said: "This season we must be even more competitive - which I believe is possible. My goal is to help take the team back to the top."The season will start in Australia on March 17 2013.