LONDON, UK - Formula 1's European season fires up in Spain with Lewis Hamilton and Mark Webber leading a fistful of drivers jostling to become the fifth different winner in five races.What was the most predictable of races, with Barcelona's Circuit de Catalunya used in pre-season testing and holding no surprises for even the rookies on the starting grid, now looks far from clear-cut.Four drivers have taken it in turn to win and lead the championship since the season opener in Australia, with Webber's double world champion team mate Sebastian Vettel currently in the lead.McLaren's Jenson Button, Ferrari's Fernando Alonso and Mercedes' Nico Rosberg have also won.There have been eight different drivers from six teams on the podium so far.Not since 1983, when Rosberg's father Keke was racing and a year before Niki Lauda clinched his third title, has a campaign started with five different winners but history could well repeat itself on May 13.McLaren's Hamilton, the 2008 champion who was on pole in the first two races of 2012, said: "We had a great race there last year, I pushed Sebastian all the way to the finish. I think we have a comparatively stronger car this year, so I hope we can have another strong race."I think it's going to be one of the toughest tracks of the year for overtaking, but I'll be hoping for a strong performance in qualifying in order to make it as straightforward as possible in the race," said Hamilton.Red Bull's Webber has started on pole for the past two years in Spain, and won in 2010 at a circuit where the top slot has translated into victory in 10 of the last 11 races, and knows he has the car to do it again.Webber said: "I like the Barcelona track, we do a lot of work there and it's a track that's been good to me in the past, so I'm looking for a strong weekend."ACID TESTKimi Raikkonen, the 2007 champion with Ferrari now on a comeback with Lotus, was second last month at a troubled Bahrain race with French team mate Romain Grosjean third. Both have to be considered.So too does seven-times champion Michael Schumacher, even if he has not been on the podium since he made his return in 2010 and has been critical of the Pirelli tyres, given that Mercedes team mate Rosberg won in China.Schumacher has won more often than any other driver in Barcelona, six times in all.Barcelona has long been held up as a benchmark, an acid test where the championship moves up a gear, but in such a close field with the cars divided by mere fractions of a second even that may no longer be the case.Red Bull boss Christian Horner said: "Usually Barcelona is a pretty good indicator of car performance: if a car works well there it tends to work well in most places. "Whether that still applies this year, who knows? I'm sure most teams are bringing upgrades of varying degree. It is the first European race so traditionally that's where teams will introduce new components to their cars and we're no different to that. It will be fascinating to see the evolution amongst the teams," he said.McLaren are hoping to have a higher nose on their car after trying out the change at the Mugello test while Lotus were fastest in Mugello with Grosjean.Lotus team principal Eric Boullier said: "We've been able to look after our tyres quite well during the races so far but the Barcelona track is very abrasive, especially for the front left tyre. "Maybe we'll do a better job than our rivals in this area. The only question mark is our performance relative to the temperature," he said.Stay with Wheels24 for the Spanish Grand Prix weekend.