Pirelli have stated they're hopeful of avoiding four stops in Spain. However, as the circuit's hard on tyres that may compromise the hopes of Ferrari and Williams, both of which had to make an extra stop compared to cars ahead of them in Bahrain.
It's also worth remembering, for the race, that the run to the start is the longest of any circuit, so Mercedes-powered cars should love it, and Renault less so (although I expect the performance gap to have narrowed somewhat).
During the weekend it emerged Renault were getting annoyed with late payment from some teams (probably Lotus and/or Caterham) and was threatening that it may stop supplying engines to the relevant team(s) if it doesn't get paid.
The tyres for this weekend are hard and medium.
There's an emphasis on aerodynamics, which will help Red Bull.
Mercedes have tightened the packaging at the rear of the car to increase aerodynamic efficiency at the cost of heat dissipation, but have deliberately done this after the hottest races of the year in the initial fly-away period of races. They may have over-egged the cake, however, as Rosberg suffered quite a lot of heat in the cockpit during P1 and didn't do many laps. In P1 Hamilton complained about high tyre degradation, which may well be a factor in the race.
Vettel had a reliability failure in P1, which turned out to be wiring loom damage that also meant he couldn't make P2. Not a great start to the European part of the season for the defending champion.
In P1, Hamilton led the way, followed by Button, Ricciardo and Alonso. Then came Rosberg and Raikkonen, with Magnussen, Maldonado, Perez and Massa rounding out the top 10.
Hamilton was also top of the timesheets in P2, half a second ahead of Rosberg, who was half a second faster than Ricciardo. Alonso and Raikkonen were next, followed by Magnussen, Button, Massa, Maldonado and Kvyat.
Raikkonen seems to be more on the pace, after the first two practice sessions. Then again, I'm reasonably sure that seemed to be the case at a previous race, but he fell away later in the weekend. Force India and Williams seem to be struggling to break into the top 10, with Perez once and Massa twice just edging in.
Lotus, are looking rather improved, with Maldonado making it into the top 10 both times. McLaren got both drivers in the top 10 in both practice sessions completed at the time of writing.
Vettel really could've done without the reliability woe. New chassis, new parts, and he'll have wanted to get a good start to the European leg of the season. I don't think he's completed one flying lap, so in P3, just an hour long, he'll need to sort out qualifying and race pace.
At this stage, it looks like business as usual for Mercedes, probably followed by Ricciardo and Alonso. McLaren and Lotus on the up, Williams and Force India going backwards (relatively). But, there's still P3, qualifying and a race to go and we'll only know for certain once the chequered flag arrives.
During P3 McNish opined that teams would prefer a 2 stop strategy, whereas those who are hard on tyres would be forced onto a sub-optimal 3 stop strategy.
Vergne got a 10 place grid penalty for his wheel coming off in Friday practice.
P3 had Rosberg ahead of Hamilton by nearly a second. However, Hamilton aborted his only qualifying run. Prior to that the Briton was very slightly behind Rosberg (less than a tenth). On pace the Silver Arrows were over a second ahead of third-placed Alonso, with Massa very impressively just a whisker behind his former teammate. Grosjean was almost half a second down the road with Magnussen and Ricciardo very close together, with Button, Maldonado and Vettel rounding out the top 10.
Force India are reportedly struggling with tyre temperature. They may be kinder to tyres in the race but suffer badly in qualifying. Red Bull were pretty poor in P3 but that may well be sandbagging.
As may have been noticed from elsewhere, I've had some computer issues lately, so I will not be betting this weekend (I want to wait and see whether they recur. I'm hoping they're resolved). However, I will tip if I see something that looks good (this will be the first occasion I've tipped without backing something myself, but I'm sure readers will understand my caution).
Bets I considered were:
Perez top 10
Grosjean/Maldonado top 10
Lay Vettel top 10
Rosberg's odds on Betfair were 3.8... that's pretty tempting, actually.
Perez to be top 10 was just 2.5, which is too short, particularly given the very poor performance in P3 by Force India. So, no bet.
Grosjean and Maldonado had even shorter odds, and given the possibility of reliability failure from Lotus I was not tempted.
Vettel's lay odds were only 1.45. Again, too short (or not short enough depending on how you want to phrase it).
I think I might tip Rosberg. There was only half a tenth between the two chaps in sector 3 in P2 (P1 doesn't count because Rosberg missed most of the session and P3 can't because Hamilton aborted his qualifying run and didn't set a sector 3 time that's comparable to Rosberg's). On that basis they're basically even, so if I were betting I'd back Rosberg, due to the odds.
So, a tip: Rosberg for pole at 3.8.
Let's hope qualifying's exciting, the bet is profitable, and I don't suffer any more technical woe.