As testing progresses, inevitably the performance window of each car narrows dramatically. The engineers hone the setups and build their understanding of how the car is working, so the differences that separate each machine are reduced. On day eight of pre-season testing (for most of the teams at least), you're looking at a grid of cars approaching race readiness.
Take Felipe Massa's Ferrari as the example. The F2012 looked a better-balanced machine on Friday than it did earlier in the week in the hands of Fernando Alonso. Superficially, that's great news for the Prancing Horse and it's certainly evidence that the Brazilian was being honest when he hailed the improvement in the car. But all things are relative and when you look a little closer at how it behaves on track, the same concerning traits are there.
Rewind to earlier in the week and Alonso was relying on significant steering and throttle adjustments at the transition from the Turn 2 left-hander into the long, fast Turn 3 right-hander. On Friday, Massa wasn't having the same scale of trouble, but the rear instability was still there. Instead of the effortless transfer of the weight from one side of the car to the other, Massa had to control a moment of rear end uncertainty as the car reset itself. The Ferrari no longer looks like it's on castors, but it's far from the first car you'd jump into given a free choice.
Webber's Red Bull looked superior to all rivals in mid-speed corners © LAT
But as this process goes on, the most refined car remains the one that caught the eye right from the off. 'Best team produces best car again' is far from a shock, but while the laptimes were decent, it was once again the poise of the car that impressed. Mark Webber could put the Red Bull RB8 pretty much wherever he wanted. When the rear did break, it was only in search of the perfect rotation on turn-in. At Turn 3, the Australian was happy to take the high line on occasions, perilously close to the growing collection of marbles offline. At the Turn 5 left-hander, the front end bit beautifully and at the exit of the chicane, no car spent less time modulating the throttle. Make no mistake, this is the car everyone is shooting at right now.
As we saw a few days ago, McLaren is currently the team best-equipped to do that shooting, and the MP4-27 continues to look strong relative to the Red Bull in the fastest corners...even though the RB8 blows everything else out of the water in medium-speed traction. But one car that also appears to be not too far off is the Mercedes. As team principal Ross Brawn has pointed out, it's not a winning car right now, but it looks strong on track.
Several things stood out about the Mercedes. On turn-in, the front end bit extremely well and allowed Nico Rosberg to commit to his line with the minimum of fuss. Also, while both Rosberg and Brawn were not particularly delighted with the levels of tyre degradation achieved, the Mercedes appeared to retain its relatively benign handling characteristics through the near-continuous corners of Turns 1 through 5 even when well into a stint on hard rubber. While this is no reason to get the bunting out in Brackley, it suggests that Mercedes is well-placed at least to edge forward in terms of relative performance.
Speaking of the Mercedes long runs, the Williams also caught the eye on Friday. The FW34 was pretty unimpressive at Jerez two weeks ago - in slow corners in particular, but the car is now looking like a tidy midfield proposition. With more miles completed than any other team - 2334 over the past eight test days - the calm, methodical approach has paid off to the point where on long runs, the car looks very consistent - even if its outright single-lap speed isn't exactly eyecatching.
The new Williams looks a better-handling car than its predecessor © LAT
On track, Pastor Maldonado looks a lot smoother than he was at times last year, indicating that, if nothing else, this is a better-handling car than its predecessor.
The same couldn't be said for Jean-Eric Vergne in the Toro Rosso. In the fast corners in particular, he had a whole heap of oversteer to deal with and was pretty ragged at times as a result. Not that it appeared to overwhelm him. It was a similar story for Kamui Kobayashi in the Sauber, who appeared to find it very easy to overstep the line and have the rear snap on him in the medium-to-fast stuff. It's no coincidence that two cars perhaps lacking a little in the way of rear downforce were the most spectacular to watch.
So what's the bottom line? Right now, the smart money remains on Red Bull with McLaren as its nearest challenger. Thinking back to how the McLaren looked here last year pre-season, that's a vast difference for the Woking team. Right now, there are three big teams - the aforementioned top two and Mercedes - with reason to feel pretty happy and a fourth - Ferrari - relived at least to have ironed out some of its troubles.
Come the end of next week's test, we will know if Red Bull keeps hold of the pre-season favourite tag that it has held since day one at Jerez.