All the cars I posted were street legal. And since they're all computer controlled, I can't imagine they'd be any more "temperamental".
we built an eagle talon for a guy. dyno'd the engine to almost 900 hp under boost. it wasn't an AWD car. we had also installed an aftermarket computer control system.
i had set the fuel, timing, and boost curves to what the engine builder told me to. they were to stay at that setting for the first 1k miles. he also had up turn down the rev limiter to 4500rpm.
the dude drove it just as he was instructed, then brought it back after the first 1k miles. i turned the boost back up, re-set the fuel, timing, etc.....rev limiter to 7k.
the engine lasted 3 weeks. this was a reputable engine builder too. it blew the rings i think, as when he went into boost, it blew the dipstick out of the tube.
you can make big power from little engines. you can't do so reliably. it's proven. fords, chevies, and dodges are still running from 40 years ago.
do you REALLY think any of this boosted junk will be?
ooo....in japan, don't you have to replace the engine by law after 40k miles/? and isn't the skyline only available there?