Formula 1 returns to Europe this weekend, marking the start of the European season. To many teams it's a welcome return home, but more crucially it's an opportunity to make key upgrades to their cars. The Spanish Grand Prix is regarded as the most important race of the season. This is due to the mixture of high, medium and low speed corners, around the track as well as how harsh the surface is on the tyres. It’s the same reason that the circuit is used in testing, as the circuit presents a fairly balanced track to develop on. Mercedes and Ferrari are set to do battle at a circuit infamous for high tyre wear, which could play to Ferrari’s advantage come race day. Ferrari have made a number of radical new updates to the SF15-T, they claim over 70% of the car is new. The Scuderia seem to be back on form again with the pace of Kimi Raikkonen looking strong in the closing stages of Bahrain, and Niki Lauda telling the press "Ferrari has closed the gap from last year to this year to nearly zero” and that they have “increased their power by about 45 horsepower”. This is sending a message throughout the paddock that Mercedes are acknowledging Ferrari as a real threat, not just to the race but to both Constructors and Drivers Championship overall. McLaren could also be knocking on the door for points this weekend, which would be a joyous sight for many given the turbulent season they've had so far. When speaking earlier today regarding scoring points, Jenson Button really did hit hard on the fact that he wouldn't be celebrating if he did it. A points score for McLaren would be a major boost for the team, especially Button, who only managed to complete a total of 5 laps across the whole weekend last time out. With Fernando Alonso finishing just a few seconds off 10th place in Bahrain, we could see McLaren return to the top ten, especially with upgrades arriving for the weekend. However, Fernando Alonso currently has an eye infection which is limiting his vision out of one eye, he hasn't been seen to have taken his sunglasses off yet this weekend, he joked during the Thursday press conference that it was because of his sponsors. The majority of teams will see new parts and upgrades, excluding Manor who are focusing their efforts on building their 2015 car for Belgium. All sessions this weekend will hopefully prove to be very interesting, with Red Bull hoping to improve their engine reliability, and Williams upgrading their aerodynamics package. Lotus have claimed this weekend that they are ready to join the “second group” with their latest updates, although their new ultra short nose has failed a crash test, meaning they will be unable to use it for the race on Sunday. The team are hoping to have it ready for Canada. This would mean they would still be at the tail end of the midfield with the likes of Force India, who’re still on the back foot in terms of development of their 2015 car, and Sauber who’re rumoured to be running out of money to develop their 2015 challenger. This could be a great opportunity then for Torro Rosso to capitalise on the rest of the trailing midfield, with the car proving to be on pace at the hands of Max Verstappen and Carlos Sainz, providing their Spain updates prove effective. Stat Attack: The Hard and Medium Compound selected with the expected performance gap between each tyre compound to be around 0.8 to 1.2 seconds a lap This is the 45th Spanish Grand Prix and the 25th to be held at the Circuit de Catalunya Track consists of 16 corners - nine right and seven left - and is 4.6km around one lap From the past 10 races the pole starter has won eight times Lewis Hamilton driving for Mercedes won the 2014 Spanish Grand Prix. Pole lap record: Mark Webber (Red Bull) 1:19.995 (2010) Fastest Lap record: Kimi Raikkonen (Ferrari) 1:21.670 (2008) Weather: sunshine all weekend with highs of 27,24 and 26 for Friday, Saturday and Sunday respectively, all temperatures in degrees celsius. Who do you feel can win this weekend? Can McLaren score points? Will Fernando Alonso’s eye infection affect his performance and do you feel he is safe to drive?