The added intake piping probably adds a little lag, but the turbo placement should make up for that. The 2010 Legacy GT had a similar turbo placement while still running an EJ series engine. Reviews all say it has much better power delivery than the 2009 Legacy with the old turbo placement.
The new motor definitely has a great low end. Peak torque at 2000 rpm and holds it to 4800. This chart is for the 296 hp Legacy FA20DIT in Japan.