Have you considered BMW i3 wheels?
Those weigh more at 7,5kg but perhaps the slim formfactor should improve mpg.
Drawback is bolt pattern and odd 19 inch rubber, but the bigger offset should allow for adapters to get it legal.
Otherwise a costfree fix it is run with absolute minimum level of liquids, fuel, water, oil, washerfluid but presume you do that already.
Wonder what would happen if you put a titanium/aluminium shape of 1 liter in the bottom oil pan to displace 1 liter of oil reducing the total amount from 4,2ish to 3,2ish. Alternatively a custom bottom oil pan.
What about to remove the antiroll bar? Inner wheel plastic housings? Brake shields?
Those weigh more at 7,5kg but perhaps the slim formfactor should improve mpg.
Drawback is bolt pattern and odd 19 inch rubber, but the bigger offset should allow for adapters to get it legal.
Otherwise a costfree fix it is run with absolute minimum level of liquids, fuel, water, oil, washerfluid but presume you do that already.
Wonder what would happen if you put a titanium/aluminium shape of 1 liter in the bottom oil pan to displace 1 liter of oil reducing the total amount from 4,2ish to 3,2ish. Alternatively a custom bottom oil pan.
What about to remove the antiroll bar? Inner wheel plastic housings? Brake shields?