Zigrat the G10 is not a G6 with MW50, the G6 has a DB605A while the G10 has the much more powerful DB605D.
This engine is very different than the 605A, more powerful allaround and much better at high alts. Plus many of the 605D had 100 octane gas and MW50 called the DB605DCM this was one hell of an engine. I dont know what our G10 has, but its pretty fast.

Anyway the speed of a G10 without MW50 is 428mph, with it it should go up there with the K4 ah around 450mph.
I think the current Harmann G6 we have was a DB605AM with MW50 and it should gat its MW50 added.
Then we could introduce an earlier 109G6 without MW50 and with the standard framed canopy but with the Galland Panzer glass head armor, as these were very common on early G6 with the old canopy.