You are right with the direct injection, they have something like 2900/3000psi of pressure with those injectors. They also have pistons with a kind of a "dome" shape to prevent "knocking" wich occured on high compressions motor.
They took the best "route" for better consumption, by using a 100 years old technology (internal combustion motor) and making it better instead of using hybrid or electric technology.
Yes hybrid are nice for people who want to show their concern for environment but in reality they are too expensive and not really fun.
Electric car are useless in normal driving condition because of the range.
Mazda is really hitting hard with the Skyactiv technology IMO.

 

is this technology similar to F1 cars? they have really small motor, but tons of HP and very fuel efficient (so they carry less fuel weight)? in a few years, will ppl salvage the engine and put it on their S2000?

 

^ Yes or put in motorcycle.