I'm looking into this again. I just weighed my stock wheels and tires, they are 45.6lbs.
The 16" Enkei RPF1's 17x7" are 14.6lbs
Ecopia EP422 are 25lbs
Champion Fuel Fighter tires are 25lbs
That would be 39.6lbs total, per wheel. A savings of only 6lbs per wheel.
I'm not sure that it would be worth the investment. I'm still curious as to if anyone has gone with the RPF1's or any other lightweight wheel. I'm wondering what they experienced when it comes to range.
I would expect to see an easily measurable improvement in efficiency with a 6lb per wheel weight reduction.
In my Prius days, I noticed a drop from 43 to 37 MPG (about 13% decrease) when I increased my wheel weight by 6.5lb.