EDIT: Updated. Car purchased!
The Insight found a new home, and I've moved overseas to New Zealand. Shortly after landing I picked this up:
Vehicle is a 2015 Mazda MX-5, which is not called a Miata anywhere but the US. I originally wanted the most basic base model, but made a call to get a few features (and some weight) I didn't care to have, in order to have a few others that were nice to have, at the same price. It has 56,000km (35,000 miles).
It's a Japanese import, and comes with an engine you can't get in the US - a 1.5L Skyactiv G engine, 129hp with a 14.0:1 compression ratio. It's hard to find the weight for this exact variant, but the base spec is officially 990kg (2180lbs) and best I can tell, this trim has ~20kg (44lbs) of extra "stuff". It's still around 108lbs less than the US base model.
Fuel economy ratings are:
30mpg City (7.8L/100)
48mpg Highway (4.9L/100)
39mpg Combined (6.0L/100)
Generally not relevant to fuel economy, but compared with the JDM base model, this has:
-Limited slip differential (vs open diff)
-Larger 280mm brakes front and rear (vs 258mm F / 254mm R)
-Alcantara interior (vs plastic)
-Recaro heated seats (vs cloth)
-Touchscreen (vs buttons and knobs)
-Bose 9 speaker sound (has a small subwoofer, extra headrest speakers)
-Adaptive LED headlights (vs fixed LED)
-Lane keep (which will stay disabled)
Additionally, the previous owner:
-Changed out the 195/50r16 tyres for 205/50r16 with a more aggressive compound.
-Deleted the sound tube
-Installed lowering springs, -20mm (0.75") height and +20% spring rate
First thing will be to get a baseline fuel economy. After that, I plan to raise the tyre pressure, install a lithium battery (from the Insight), underbody paneling, maybe a partial grille block, rear antenna delete (or smaller antenna). When it needs tyres it will get LRR rubber. Trailer hitch is probably in the cards. I also plan to get a tune (increases horsepower from 129 to 158) and see if that hurts or helps.
Some items that are interesting but aren't cost effective, that I'm window shopping:
Lightweight brake kit - 22.2lbs savings
Lightweight wheels - 15lbs savings
Lightweight seat rails - 13lbs savings
Along with the lithium battery (-19.5lbs), this would be a total weight savings of 69.7lbs, bringing the car down to (potentially) 2154lbs. There's another 10lbs to be shaved if I eventually go with aftermarket suspension.