When I bought my Duratec plus 4 it had the full Williams Motorsport stainless manifold and exhaust/sports cat along with the ITG air filter conversion already fitted. I've had my car on a rolling road and it produced 155bhp at 6000rpm and 148lbft torque at 4800rpm. Assuming Fords figures are correct that's a 10bhp increase only.
Ford's figures are from the flywheel. Did you take yours from the rear wheels?
As dyno figures cannot be compared to anything but the same car with the same dyno operator,
assuming the dyno has not been re-calibrated between the tests your best determinant is how you "feel".
gmg
