Car appreciation... the aesthetics, the engineering, etc

I wonder what the least power you could have fun with is, if you made a really, really light car?

i.e. a carbon chassis, two seats, narrow and light wheels etc etc with (say) a 300cc twin cylinder, or perhaps even smaller?

Is even that much needed with skinny tyres?

Define 'fun', I guess.

Have you ever owned or been driven in a Mini? On standard tyres they feel like a street level Spitfire trouncing the Heinkels. Even a 1000cc is fun and 20mph feels like 50.

Hell even a 2CV is fun, and what are they? 29 bhp.

Either Fifth Gear or old Top Gear once demonstrated that you could learn to hold a perfect drift at 20 mph on a wet roundabout in a morris minor.

A smallframe Vespa is fantastic fun at only 5.6 bhp.

light weight + stiff chassis + soft springs + limited grip = fun with not much power. Make it too competent, with wide tyres, stiff springs, etc, and you need to make it much more powerful for the same buzz. In my Merc 40 mph feels like walking pace. On a bicycle it's scary and exciting.