234 hp for 3K sounds like a tall story to me ,and a 3SGTE self mapped on megasquirt good luck with that !
150 hp per litre is possible the last engine i built that gave that was a non turbocharged cosworth engine wich cost nearly 30k and the little Vaxhall corsa engines 1400cc give 160hp approximate cost 10k
And as for turbo engines being laggy turbos have moved on a long way.
The last 500hp subaru i built had 28psi of bost at 1600 rpm with over 350 ftlb of torque at 1600rpm with over 500ftlb at 5200rpm approx cost 30k
Anything is just about possible but there are three variables when it comes to engines
CHEAP
RELIABLE
POWERFUL
Pick two options from above
Now get your foot down