The IS-Fs V8 engine is based on the LS limos, but has been thoroughly revised, so it now churns out 417bhp and a hefty 372lb ft of mid-range muscle.
Floor the accelerator from a standstill and youll hit 62mph in just 4.8 seconds, while the automatic gearbox with eight (yes, eight) closely stacked ratios ensures theres next to no let-up until you hit the speed limiter at 168mph.
The engine emits a muted V8 rumble at low revs and a glorious race car howl above 3600rpm. However, the road noise that finds its way into the cabin is far less appealing.
Gearchanges are smooth in automatic mode and super-quick if you use the steering wheel-mounted paddles, but manual upshifts are rather jerky and the gearbox is overly keen to kickdown when left to its own devices.
To transform IS into IS-F, Lexus has stiffened the body, reworked the suspension and fitted brakes the size of dustbin lids.
You have to watch your speed when entering sharp bends because of that big, heavy engine upfront, but the steering is accurate, theres loads of grip and you can alter how much help the stability control gives depending on your mood.
Sadly, you cant alter the ride, which is firm and unsettled.