In the UK ca18det bottom ends with 8v sohc ca20e style heads are making 200hp atw.
Even older head technology and with forged internals like Piggys ca and the right
manifolds, turbo and tune can make over 250atw no sweat.
There is a ca18det with 411 atw
http://autospeed.com/cms/article.html?&A=1249

Old bmw 2002 engine blocks where used in f1 turbo setups in the early 80s
only after the engines where seasoned with over 100,000klms then a
twin cam head similar in design to the ca18de where used with exotic
fuel for over 1500hp in sprint tune.

ca18det turbo engines give better fuel economy and performance compared
to more cylinders, capacity and price per unit.
They are also lighter than Sr and rotaries by a long margin.

The ultimate turbo Nissan 4 cylinder is still the FJ20ET nothing comes
close and nothing forever will from Nissan problem is weight.