There have been couple of posts requesting the use of 72lbs manifold pressure in P47 and also to use the tweaked P38 engine manifold pressure for in game use.
I think u will really force AH to a real nightmare once u want all this tweaked engines.
From my researches about LW units i know that there was rarely any FW190D9 that wasnt tweaked in the frontline workshops. Like the P47 engine the JUMO 213 could produce much more power, without taking serious dmg or wearing out to fast.
So if we get a tweaked P47 and P38, we should also have to get the multiple tweaking option for the D9.
Most common was the "Ladedrucksteigerungsrüstsatz" which enabled the jumo 213 to produce 1900hp instead of the normal 1750hp. With this Rüstsatz, climb and combat power could be mantained indefinitely, normal emergency power (without additives like MW50, C3 injection or GM-1) could be used for 30 mins instead of 3-10mins.
MW50 injection in wiht this rüstsatz was done at 1,8ata and gave 2100hp for up to 10mins. the 2100hp are for B4 fuel, the C3 in use with the D9 units which was higher octane fuel (96 instead of 87) would produce even more HP. possible is that MW50 wiht 1,8 ata and C3 gave 2240HP, but that is not certain yet.
Another option was the A-Lader, which was a special design for low alts, ad produce and immense hp increase (exact HP not yet verified) and made the D9 a real hot rod down low.
U can look at the data at this page
http://jagdhund.homestead.com/files/Dora.htm i contacted the designer of this page, and he has collected this data from various books but mainly from orignal data tables and he also did many interviews with engineers etc.
he is building this page cause yet there is no book that includes all the various eng modifications and options for the JUMO213, he statet he is thinking of writing a little book maybe over this issues
As a conclusion i would say, that tweaked engines only would increase the superiority of some late war planes over most earlier planes, but the relations between the late war planes would not be changed anyway.