I am not sure but *I believe* the lightest wheels that are 16 x 17, have the stock NSX offset, take the stock lugs, and accept the stock tires are the Forgeline RS 2 piece wheels - like I have on my car.
The RS 16" are 17.2 pounds and the 17" are 18.75 pounds. So the fronts are a slightly hevier and the rears are slightly less - but the total is a couple pounds less then stock.
These are the same wheels on the CART NSX, the old Peter C. CompTech NSX, and most importantly Nick M.'s car in St. Louis!
BTW - if you like stock wheels - you can't go wrong and there always seems to be some for sale on this forum.
Good luck!
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Nick M
91' Red/Black with Many Mods
99' Honda Odyssey with Many Kids