Improving on excellence is never a simple task, and it's even tougher with a laptop as good as Sony's Z Series: indeed, the VAIO Z51 already sits on our A-List as the ultraportable of choice.
But instead of eking out a little more battery life, or trimming a little more weight, Sony has taken a radical approach. The stamina-focused ultraportable of old has been rebuilt from the ground up, and completely transformed.
The Z11 cuts a professional dash: all matte black and gunmetal grey, with a few scattered status lights. It's so understated we wondered how it could justify its huge price. That became clear very quickly.
The superb keyboard has been improved. The keys aren't just backlit, with an ambient light sensor to fade them in and out, but they also have a crisper action. The trackpad has been pushed a few millimetres further from the spacebar to prevent stray thumbs from jogging the cursor unintentionally - a minor issue with the Z51.
Build quality has taken a leap forward too. The Z51 is sturdy for a 1.49kg laptop, but it wasn't perfect. This new addition to the Z Series sees the weight drop to 1.41kg (1.83kg with charger), but twisting the chassis with all our might revealed only the tiniest bit of give, and it took some vicious prodding on the lid to cause any showthrough on the display.
That 13.1in display gets a Full HD, 1920 x 1080 resolution, and it offers eye-popping brightness and glorious colours. The only drawback is that you'll need to use Windows 7's text-scaling abilities to avoid squinting at tiny fonts.
In this particular model in the Z11 range, with part code VPCZ11GGX, there's 802.11n dual-band WLAN and 3G support at 7.2Mbits/sec HSDPA speeds, so you can slot in a SIM and access the network of your choice.
The boldest change, however, is inside.
Despite being so small and light - and note Sony squeezes a DVD writer inside - we've never seen a portable tear through our benchmarks so viciously, with a 1.80 score besting even the dearest workstation laptops we've seen.
Sony has Intel and Samsung to thank for that. The VPCZ11GGX uses a new Core i7-620M processor, with 8GB of DDR3 RAM.
Built on the 32nm process, it's cool and efficient, and the score is more impressive when you consider it drops the quad-core, eight-thread setup of older 45nm parts for a more modest dual-core, four-thread architecture, and integrates graphics onto the chip.
Sony uses a hybrid graphics system, meaning duties can be passed to a discrete Nvidia GeForce GT 330M chipset for more power-hungry applications. It's possible to flip between the two at will, and the three-way switch above the keyboard also has an automatic setting.
Samsung's contribution is four 64GB SSDs, which Sony employs in a striped 256GB RAID0 array. We ran the AS SSD and ATTO Disk Benchmark suites and read performance peaked around 600MB/sec, with write speeds at around 430MB/sec. It helps make the Sony that rarest of beasts: a featherweight workstation.
The one glaring issue is that SSDs suffer from performance degradation over time and, crucially, RAID controllers prevent Windows 7 from activating the individual drives' TRIM support to alleviate the issue.
The only solution for power users will be to wipe the drives, rebuild the RAID array and reinstall Windows once such degradation occurs. All this power comes at a cost to battery life too.
Where the VGN-Z51WG/B managed just over ten hours of light use, the VPCZ11GGX only just tops half that. Switch to High Performance mode, and you'll get barely more than an hour.
Other than this - and bear in mind 5hrs 26mins of light use is far better than most high-performance laptops - the VAIO Z11 is a stunning, and genuinely portable, workstation. It has some minor flaws, but if portable power is what you're after, you won't find anything better.