I just compared the new Mossie with the old one, and there are some intresting changes to its performance:
First off, weight: with 50% fuel, no ords and the hvy gun package, the new one weighs 17920 lbs, the old one 18726.
Secondly, speed: OTD (MIL/WEP): new (322/357) old (324/339)
Thirdly, agrarian: 200-300 (MIL/WEP): new (77s/40s) old (67s/48s)
And finally, climbrate: 0-5kft (MIL/WEP): new (~2,3 kft/m /~3,3 kft/m) old new (~2,6 kft/m /~3,2 kft/m)
It's pretty clear that the new Mossie seems to be down on power at MIL settings compared to the old one. It cannot benefit from the lower drag at all in terms of speed and clearly suffers in acceleration and climb. The gauges do read the right numbers though (2850/+9lb). WEP performance seems about right.
