The superleggera is VERY light, due to how OZ constructed them. The SSW's look like a cross between the superleggeras and ultraleggeras...
...but how its constructed I wouldn't know...
OZ Superleggera Specs:..........OZ Ultraleggera Specs:
15x7 ET37 10.7lb (4.9kg).........15x7 ET37 12.4lb (kg)
16x7 ET37 14.3lb (6.5kg).........16x7 ET37 14.5lb (kg)
17x7 ET37 15.1lb (6.8kg).........17x7 ET37 16.0lb (kg)
18x7 ET42 16.5lb (7.5kg).........18x7 ET42 17.6lb (kg)
From MINI2.com.........................From
WHEELWEIGHTS.NET
Not ahd any luck finding the weight of SSW Stings, but if there other wheels are anything to go by, they're unlikely to be as light as the super/ultra leggeras.