What is it?
Meet Lexus's answer to the BMW M3. Like its German rival, the IS-F has had a V8 engine shoe-horned under its bonnet, although in this case one with 5.0-litres of displacement and with drive dispatched to the rear wheels via an extremely clever eight-speed gearbox.
Despite the extra capacity, the F's 417bhp is almost identical to that of the M3's higher-revving 4.0-litre motor, but it has far more torque to call on - 372lbft against the BMW's slightly anaemic 295lbft.
What's it like?
Pretty impressive. Indeed, if you were about to sign an order form for the new M3 it might be worth waiting three months to have a go in the IS-F.
The engine is a work of art, lacking much urgency at lower revs but waking up at around 2500rpm, and then pulling with increasing vigour to the 6600rpm at which peak power arrives.
Despite sharing an identical 4.8 second official 0-62 mph time with the M3, the IS-F feels subjectively quicker off the line, thanks in large part to an amazingly vocal V8 soundtrack.
The eight-speed transmission is a development of the system already fitted to the LS460, but with the ability to take direct control of gear selection via paddles behind the steering wheel, and with a lock-up clutch that can operate from second to eighth gears and dramatically reduce both shift time and the normal autobox feel of a slushy change between ratios. It's not perfect, sometimes getting confused when left in "Drive" and, even at its quickest, still not capable of matching the seamless shifting of a twin-clutch system. But it's vastly superior to the lunge-prone SMG system that BMW still foists on M5 and M6 buyers.
The rest of the driving experience sticks close to the M3 benchmark, too. The IS-F is undoubtedly the most dynamically focussed Lexus yet, with well sorted suspension and steering. At 90 percent commitment it's very impressive: agile, point-able and very grippy. Beyond that the front end washes out in anything except slow-speed corners, even with the stability control fully isolated. With the electronic nanny kennelled the IS-F can be persuaded into smoking its rear Michelins like a good 'un, but it's not as much of a hooligan as the eminently driftable M3.
The biggest disappointment is with the tame styling, though. Buyers get a new front bumper, some vents inset into the trailing edge of the front wheel arches and quad exhaust pipes as the rear, but it doesn't feel different enough from the lesser models in the range, especially when you consider its very serious £51,000 pricetag.
Should I buy one?
With near-identical performance and pricetag to the M3, the Lexus looks set to give the BMW a serious run. It's more practical than the (currently) coupe-only M3 and the transmission is better suited to everyday use. Now all we need is the UK arrival of the Mercedes C63 AMG and things will get really interesting.