Honda S660
Why 7.8: A mid-engine roadster with a real 6-speed and 63 hp — the purest proof that involvement has nothing to do with power. JDM-only, dailyed in Japan, grey-imported by people who understand.
Layout
Natural habitat
Ride comfort
Sound
A 658 cc turbo triple sits behind your shoulder, so induction and wastegate reach you directly rather than through a bulkhead, and it spins to 7,700. But 64 hp of kei three-cylinder is thin and thrashy however hard you rev it. Character, not tone.
3-cylinder · turbocharged · 7,700 rpm redline · rated 5.0 / 10 for engine sound
Market value
Median asking price, good condition · €11k (2016) → €18k (2026), trending up · illustrative data
Child seats · ISOFIX
There aren't any — strict two-seater.
Confirmed absent — Honda's own child-seat compatibility chart explicitly lists the S660 as excluded from ISOFIX support.
The Japanese owner's manual offers no switch or sensing workaround for a front child seat — its only advice is to slide the passenger seat as far back as possible.
Honda S660 owner's manual (honda.co.jp child-seat installation page) + Honda Japan child-seat compatibility chart (2017, via compactcar.net)
The long version
In Japan the kei-car tax and parking rules make this the rational choice, not the enthusiast indulgence it becomes the moment it is grey-imported into the US — nobody here gets a registration discount for 63 horsepower, so the import buyer is opting in purely for the driving experience. That self-selection shows: import S660s get autocrossed, canyon-run, and used daily by people who did the import paperwork specifically because they wanted a manual mid-engine roadster and refused to let displacement talk them out of it. It is the smallest car on this index and one of the most honestly used.