I have the 500 AC race car converted for the road. I just ran it on the dyno - 205 hp at 5300 and 292Nm with very flat torque curve from 3000 to 5000.
Spec is GT1446 with 300cc injectors, updated boost sensor, marelli exhaust with cat and cone filter. I believe peak boost is 1.6 bar at 3000 but it reduces to 1.1 bar by 6000. (That is the standard AC map).
Very easy to drive on the road, but feels a bit flat over 5000.
Just about to remap for more boost at the top end, so will keep you posted.