The Formula Ones teams are gathering in Spain amid excitement that the combination of KERS, DRS and Pirelli’s tyres will provide an unusual level of overtaking at the Montmelo circuit, which in the past has generated low-key races with relatively little passing.

McLaren team principal Martin Whitmarsh is just one who believes that the race will confirm how successful the 2011 technical rule changes have been.

"I'm particularly interested to see how they affect Sunday's Grand Prix," Whitmarsh said. "We've seen how DRS and KERS Hybrid have influenced the racing so far this season, so we'll see how things progress at Barcelona given that the Spanish Grand Prix has previously shown limited opportunities for overtaking."

McLaren will be just one of several teams bringing significant updates to this race - engineering director Tim Goss reveals that they will have more than 10 - having just missed the mark with them in time for Turkey. "As usual the relentless pace of upgrades continues,” he says. “We have a package of upgrades which we're taking to Spain. It's a package of about 10-12, some of which will be recognisable from the outside and some that won't be.

"Our objective is to win races and championships and to do that we have to close the gap on Red Bull. We just keep chipping away at the problem. We had a package for Turkey that we took there. We're always trying to accelerate getting upgrades to the circuit as quickly as possible. Just prior to Turkey we had a minor issue that meant I wasn't confident that the upgrade would be durable over a race distance. So we pulled out of that at the last minute. We'll re-evaluate all of our issues on Friday here."

Ferrari will also have a major upgrade, and after his podium finish in Turkey Fernando Alonso believes that he can still fight for the world championship this year.

"You know I like playing with numbers - and as I travelled backwards and forwards between home, Maranello and Turkey, I made a comparison between my first four races of last year and those of this year in the corresponding Grands Prix," he explains. "What came out of this little game was that compared to 2010 I'm eight points short (49 versus 41) but in the same four races, this year I've brought home 13 more points compared to last year (41 versus 28).

"It's true that my current gap to the top of the drivers' championship is much greater (52 points) compared to what I had after Shanghai 2010 (11 points) but I well recall that after Silverstone we were 47 points away and we only had eight races left.

"Today we still have 15 Grands Prix to come. This shows that you can look at the same thing in two different, even completely opposite ways. What matters are results and we've started to make the podium: we must do that regularly and if so I'm convinced that we will again be able to fight for the title."

Mercedes will have a revised aero package as team principal Ross Brawn remains adamant that Michael Schumacher can kick-start his fight-back here, as will Sauber, Force India, and Williams. Lotus and HRT also have big changes.

The former aim for a second per lap’s worth of progress, which could put them firmly in the midfield, the latter will be running for only the second time at home. “The Spanish Grand Prix is the perfect setting for the team to show the fans what we’re capable of and we hope to make the next step forward in front of the home crowd,” says HRT team principal Colin Kolles.

Virgin, the third of the ‘newcomers’, believe that they learned a lot about the update they took to Turkey after recent straight-line running with tester Adrian Quaife-Hobbs at Idiada in Spain.

Meanwhile, overall, Red Bull are confident of remaining the 2011 pace-setters for the fifth Grand Prix in succession.

The most prominent feature of the 4.655-kilometre Circuit de Catalunya is the very long pit straight, which also provides drivers with the second longest run from grid to first corner. A hefty 830m of that straight will serve as the DRS zone, with the detection point shortly before the final corner and the activation zone starting shortly after it, so expect plenty of passing attempts into Turn One.

However, it’s the combination of different corners in Barcelona that highlights every aspect of a car’s performance and is very tough on tyres. Pirelli will be bringing their new ‘silver’ hard tyre, which is slightly more durable over race distances, together with their established ‘yellow’ soft as this weekend’s option.

Catalunya is a popular testing venue and the teams have all tried Pirelli’s wares here on previous occasions, once last winter and twice in the pre-season official tests. Along with Pirelli’s on-going private test campaign last month, it means everyone has a lot more information on tyre performance than they did in the first four races.

The weather in Montmelo will be mainly sunny, with some cloud a predicted ambient temperature high of 24 degrees Celsius on Thursday and Friday, dropping to 23 on Saturday. It is expected to rise again to 25 on Sunday.

The Spanish circuit is largely unchanged since Red Bull’s Mark Webber won the 2010 race, the only significant alterations being higher kerbs in Turns Seven and Eight which were installed for winter testing. The race will run over 66 laps or 307.104 kilometres (190.834 miles), and will start at 1400 hours local time, which is two hours ahead of GMT.