@Hardik: Only Honda has homologated its PU so far. Ferrari, Renault and Mercedes are not required to do so at this stage but need to before the first race weekend in less than two weeks.
@noski: Tests are a good opportunity to get paddock access as you can buy it for a reasonable price. At races you have to be invited into the paddock or buy a Paddock Club pass ($$$$), but even a Paddock Club pass doesn't give you the freedom to roam the paddock at your will. At every race fans wait outside the paddock gates in the hope of seeing their heroes. There are also autograph signings at most races, but don't expect much more than a second or two in front of the driver.
@HashwanthMaripina: There were some rumours doing the rounds earlier in testing that it is the second most powerful PU after Mercedes, but I'm not sure where they originated from.
Vettel is back out on track and using the medium tyres. The Ferrari pit wall is packed and the pit board is counting down a race distance, so looks like a race sim.
@NorbertHaug: That sounds like a heavy fuel load to me.
@vs: No sign of it yet. Button in the garage with 23 laps. They said they may try one, but it seems like it may well be a luxury they are going to have to live without this winter.
@HashwanthMaripina: The Renault sounded far worse last year and both the Mercedes and Ferrari were quite rough at times. The Honda is now sounding much better than it did on those cold early mornings in Jerez, but has kept a distinctive exhaust note.
@ThePowerofDreams: The danger is that you have races ruined by drivers at the back. The blue flag system isn't perfect but it does serve a purpose.
@ThePowerofDreams: The picture is not that clear, but it's an odd place to see smoke coming from.
@HashwanthMaripina: The chassis and aero look like a big step forward on the McLaren. That's what I've heard them referring to, less so the PU that it is still getting up to speed.
Have just got back from a stroll down the pit lane. The Renault engine is noticeably quieter than Ferrari and Mercedes. Sounds like there is lots of work going on at Toro Rosso but the shutters are pulled across their garage and my ninja abilities aren't what they used to be.
Noise-wise, Mercedes has a slightly raspier sound to it than Ferrari, or at least I thought so.
Also had the sight of Rosberg catching and passing Vettel down the pit straight. I remember last year Button remarking one of the Mercs "went by me like I wasn't even there". Certainly looked similar today, though Vettel was at the start of a race sim and therefore carrying a lot more fuel than the Mercedes.
@NorbertHaug: Effortlessly is a good way of putting it.
Vettel is back in the pits. Just Nasr and Perez on track as the Force India completes 100 laps.