inlets are the same, although ACT sensors are different.
heads are the same IIRC (only erst's (S1??) had different sodium filled exhaust valves).
depends on condition really, but they fuel 200bhp fine on a cosworth(204-227bhp), probably ok to about 250bhp depending on condition, duty cycle and fuel pressure.
does depend on volumetric efficiency, turbo spec, cam etc.