Generally speaking, we're fans of the BMW Z4 M40i at PH, although truth be told it's never quite lived up to expectations. It's throughly competent and very rapid, but without being totally engaging out of the box; possibly because it's been M-fettled to leave plenty of room for something fully M blown. Which does leave a gap - one that German tuner Lightweight Performance reckons it has filled by uprating the B58 straight-six to produce a 718 GTS 4.0-rivalling 400hp.
That boost of 60hp over standard is joined by climb in torque from 369lb ft to 420lb ft, a change we’d expect to shorten the M40i’s 0-62mph time to around the four second mark. The output growth has been achieved in the traditional 21st century way, with an uprated ECU map - and nothing else. It removes the standard car’s 155mph limiter, so Vmax is now rated at 186mph.
You can, of course, add a bigger, four-tip stainless steel exhaust to give the enhanced engine a soundtrack to match, with controllable flaps to switch between modes. But it’s not essential because the power’s all there in the new code.
Lightweight’s presently working on an adjustable suspension kit for the Z4 with Bilstein to make the most of the extra power, although buyers wanting sharper handling right away are being offered a lowering spring kit, which take 15mm from the car’s ride height. New lightweight wheels of 20 and 21 inches are also offered, shod in Michelin Pilot Sport 4S rubber, with 295mm worth of the stuff on either end of the rear axle to manage the beefed up delivery.
As you’d expect, the German tuner provides an uprated brake setup as well, including higher-spec pads and hoses so pressure and feel is likely to seem enhanced. An aluminium pedal set spruces up the driver’s footwell.
Combined, it all adds up to quite a transformation. And for aspiring Z4 owners it might convincingly close the gap to more sporting drop-tops like the Boxster GTS 4.0. Although whether the changes are enough to constitute something more satisfying - or more in keeping with the M car way - remains to be seen. Still, it's a good reminder of just how pleasingly handsome a new BMW can be. And we needed that this week.
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