Not exactly an update, but I'm planning some lawn edging side skirts, and to possible extend the wind deflectors around the front and rear tires.
After reading Phase's thread about smaller wheels vs highway economy, I also thought I'd place what my wheel research has come up with. While others may not use the same size, the relative weights of different wheels ought to remain close. Some of these options become lighter than others at 15" or 17", but they don't drastically change in their rankings. It's worth noting that higher offsets (pulling the wheel's inward) are lighter, in addition to narrower wheels. Forged wheels typically have thinner barrels because the materials are stronger, so the weight savings in forged wheels are in the best place.
In the 16" size:
TWS T66-F 16”x6.5+45 10.54lbs
Mugen MF10 16x7 +43 11.00lbs
Racing Hart CP-035 16x7 11.2lbs
Sparco Viper R 16x7 11.2lbs
BuddyClub P-1 Racing QF 16x7 +45 11.33lbs (non QF are heavier)
Rays TE37 OG 16x7 11.2lbs
-Note SONIC are newer and stronger, with a higher weight rating, +37 Face 2 recommended
Rays TE37 SONIC SL 16x6.5+38 wheels 11.55lbs (?)
+42 are 11.40lbs - REV9 sells these for $3300 + 350 shipping
Rays CE28N 16"x7+42 11.64lbs (one version 11.22lbs?)
Motegi Traklite 16x6.5 +42 12.00lbs
SSR Type-C 16x7 +42 12.10lbs
SSR Type-F 16x7 +42 12.30lbs
SE37 16x8 12.5lbs
Spoon SW388 16x7.5 12.56lbs
Enkei RPF1 16x7 +43 13.70lbs
The stock 16x6.5 +45 on my car are supposedly 14.3lbs, which is already considered very light. Typical steel wheels in that size are 20-24lbs. Of the lightest wheels on the list, only TWS, Rays, and Eknei are currently in production. The rest are older lightweight 90's and early 2000's wheels.
Supposedly certain 15" wheels can fit on my car. 15's will fit over the base model ND with 1.5L engine which has smaller brakes (258mm), but the brakes on my car are 280mm (11 inches), making fitment with 15" very hit and miss.
In no particular order:
Desmond Regamaster 15x6.5 - 8.6lbs
Enkei RP-F1 15x7 - 9.1lbs
Modex Ks-Ce 15 x 6.5 Forged - 9.2
SSF 15 x 6.5 - 8.6
SSF 15 x 7 - 9.4
Racing Sparco Viper R (Japan Only) 15 x 6.5 Forged and Spun - 9
SSR Type-C (called Competitions in US) - 10.4
15 x 6.5 SSF - 8.6
15 x 7 SSF - 9.2
Volk CE28N 15 x 7 Forged - 9.1
Volk TE37 15 x 6 Forged - 8.8
Volk TE37 15x7 - 10.34
Volk TE37 Sonic 15x7 - 11
TWS T66-F 15 x 7 Forged - 9.8
More modern wheels, like the TE37 Sonic and TWS T66-F, which are stronger than older wheels, don't seem to save as much weight going smaller in diameter.
Many of these superlight wheels are not very aerodynamic. Styling trends tend to want concave faces, and spokes with sharp edges or lots of open space for showing off brakes.
The two I favor (in terms of weight and availability) are the TE37's and TWS. Here are some sample pictures of what they look like:
