The second 2014 Formula One preseason test starts on Wednesday at the Bahrain International Circuit.
At Jerez a few weeks ago, we got our first look at the new cars and drivers.
The 1.6-litre V6 turbo hybrid engines, and in particular the struggles experienced by the Renault-powered teams, dominated the headlines.
Mercedes and Ferrari looked stronger, but it's still too early to tell who has the advantage.
Hopefully, the Bahrain test will give us a better idea of who is where.
Here's what to look out for.
At the first test in Jerez, the Renault-engined teams had a rotten time. Caterham did 76 laps, but seemed to be running with everything turned right down and were painfully slow.
Toro Rosso did 54 laps, while world champions Red Bull did just 21.
There were many problems with the new Renault Energy F1 powertrain at the last test, but the major issue related to the cooling. This is proving especially troublesome for Red Bull.
The team's chief technical officer, Adrian Newey, told Autosport about the difficulties:
It was, you could argue, a result of aggressive packaging but we felt that we needed to take a few risks to try to get a good package that would minimise the aerodynamic damage of this very large cooling requirement.
The Renault seems to have a particularly large cooling requirement.
Everybody of the three engine manufacturers will have a different target for how hot their charge air is going back into the plenum and Renault have given us a fairly challenging target.
It has all sorts of advantages if we can get there, but it is not easy to achieve.
Renault have been working hard on a solution and the teams will have spent the past few weeks toiling away at finding a fix too. They absolutely need to have everything sorted by the end of this test.
If not, four teams and one engine supplier will have a serious problem.
Lotus missed the Jerez test, and though they have released a few pictures, Bahrain will be the first time we'll get to have a proper look at the E22 on the track.
The main point of interest is the asymmetrical twin tusk nose. They seemed happy enough with it, but might they switch to a different design?
Also worth a look is what cooling solutions they have come up with, and whether they can get the problematic Renault powertrain to work.
Lotus successfully completed 100 kilometres on one of two "promotional days" paid for by Renault earlier this month.
But that's only 22 laps, and there's no evidence to suggest they were at anything like normal testing pace.
Indeed, Grandprix247 reported a source present at Jerez said the car was driven very slowly and that the laps were completed in short stints.
It'll be interesting to see how they fare at this more public session.
Temperatures at Jerez were cold by the standards of F1, which tends to follow the sun around the globe.
At Bahrain they'll be a little higher. Not as hot as you might expect for a desert country (around 20 degrees Celsius is expected for all four days), but closer to the average temperatures the teams will face over the course of the year.
Mercedes and Ferrari seemed mostly on top of their new powertrains in Spain.
With cooling such a big issue with the new hybrid engines, this test will prove a better indicator of where the teams stand reliability wise.
The Jerez test was held quite early, and many of the cars we saw were very much "launch-spec" versions.
Development has continued since then.
And we should expect to see changes especially around the front wing and nose areas of the cars. The unattractive finger-noses aren't going to disappear, but some teams may move to different solutions.
Let's just hope no one copies Caterham...
Jerez was little more than a shakedown test. None of the teams pushed their engines up to the levels they'll be operating at during race weekends, and none of the drivers tried too hard either.
The tyre situation was unusual too. Pirelli supplied the teams with a special winter version of the hard compound to better cope with the low temperatures. According to Pirelli, this tyre got more use than any other.
At Bahrain we might see the first qualifying simulations and, though the winter tyre will be available here too, it won't get as much use. Time will still be left on the table, but not as much as in Jerez.
Also of note will be how close the drivers get to 2013's pace. Formula1.com has all the timing information from last year's Bahrain Grand Prix—first practice times are the best comparison to use.
Photograph taken last week in Bahrain.
Though it's seldom reported on (because not a lot happens from day to day), the Bahraini Uprising is still going on.
A police officer was killed in a bombing last week in the run up to the third anniversary of the start of the protests.
This testing session isn't as high profile as the Bahrain Grand Prix itself, so it's unlikely to attract as much attention.
But it's still worth keeping an eye on the situation.