Also to note, this was on 93 octane, no? On the Matrix dyno they typically use 92 octane for pump fuel. Not a huge difference, but should be worth a wee bit of power when tuned for. A 3" inlet green ran 360whp at Matrix not too long ago, so I don't think low 370's is unreasonable with another point of octane... especially when accounting for other car-to-car differences.
Overall, great numbers... and it seems to be in the ballpark for Mustang Dynos.