Supermarine Spitfire Mk Vb

About Spitfire maximal speed in level flight.
First. About speed difference between +9 and +16 mode.
We have two sources for +16 engine mode.
That: http://www.spitfirep....com/aa878.html (Difference in speed between +9 and +16 below full throttle altitude is near 36 m.p.h.)
And that: http://www.wwiiaircr...l_Speed_RAE.jpg (Difference in speed between +9 and +16 below full throttle altitude is 28...32 m.p.h.)
In simulator, under ideal conditions, speed increases by approximatly 34.5 m.p.h. (below full throttle altitude). And it is close to both (36 m.p.h. and 28...32 m.p.h.) sources.
Ok, now second. About maximal speed at +9 mode.
If we compare that http://www.spitfirep....com/x4922.html , that http://www.spitfirep....com/w3134.html , and that http://www.spitfirep....com/aa873.html sources, we find that in all of them we have similar maximum speed in lewel flight (375 m.p.h., 371.0 m.p.h., 374 m.p.h.,).
In simulator top speed - 367 m.p.h., but we hawe a snowguard, which decrease top speed.
But in this report (which we already considered above, when talking about +16 mode) http://www.spitfirep....com/aa878.html top speed at +9 mode is only 359.5 m.p.h., and this is considerable slowly that top speed from other three reports.
And, finally, we have that http://alternathisto...9_0-640x330.JPG data for lend-lease Spitfire with Merlin 46 from NII VVS tests (left kolumn, in k.p.h.) And this data close to Spitfire in simulator with Merlin 46 (near 10 k.p.h difference, less that 2%).
So, after all, i think that Spitfire top speed in level flight in simulator close to real test flight data.