As far as I'm aware the purpose for light weight wheel nuts/bolts is to reduce unsprung weight.. They have been used by touring cars and most race cars that don't use centre locks.. I believe the Mclaren f1 was the first car on the road to use them to, while the argument stands of they don't weigh that much less, it's not the overall weight that the save but the effect of a centrifugal force on the hub, this is also the reason fully floating discs are used along with a different vain design in the centre of the discs..
Studs should be clean from any grease or rust before fitment to ensure correct torque setting they then should be checked 30miles after the arguments being for this is having rust on a thread can mean correct tourqe is archived earlier on the thread and that a greased thread a higher torque maybe achieved I'd go with 120nm
and they look trick as (y)