Suave is right.
According to the
listed OTD speeds courtesy of Whels(Perked planes+"Big Four"/planes under 300mph with MIL, under 320mph with WEP removed from the list):
MIL:
TYPHOON 355
YAK9-U 355
F4U-1 350
P-51B 347
190D-9 346
F4U-1D 343
109G-10 337
LA-5 336
P-38L 333
P-47D-11 333
P-47D-25 329
P-47D-30 329
190A-8 327
YAK9-T 327
190F-8 326
190A-5 326
MOSQ 325
C205 321
109G-2 320
F6F-5 320
109G-6 317
109F-4 310
C202 307
KI-61 305
110-G2 305
WEP:
190D-9 375
TYPHOON 370
109G-10 366
F4U-1 358
P-51B 358
F4U-1D 357
LA-5 356
YAK9-U 355
190A-8 349
190F-8 349
P-38L 344
P-47D-11 344
P-47D-25 340
P-47D-30 340
109G-2 340
190A-5 339
MOSQ 338
YAK9-T 336
109G-6 336
109F-4 332
C205 331
F6F-5 330
...
It doesn't take a brain surgeon to see that it'll be 190 heaven.
Spitfire 'effectivity' will be controlled, since the SpitV, while a decent plane, is way too slow. Of course, their numbers won't go down, we'll still be seeing a lot of Spits. But with the N1K2 and Spit9 gone, the planes that turn well, are simply, too damn slow.
For sake of reason, let's say that the Yak-9U, F4U-1 and Bf109G-10 numbers won't rise so drastically - Yak-9U is stingy in ammo loads, Bf109G-10 is stingy in ammo loads AND a crappy high speed plane, the F4U-1 is a hard plane to manage well.
However, the Typhoon, Fw190D-9 and the P-51B is virtually unchecked now. Fastest plane with quad hispanoes, a 190 that virtually matches the P-51D, and the P-51B - a P-51 with smaller loadouts in armament.
The only big difference would be the La-5, which performance is outstanding in almost all areas as a pure A2A plane, will not be the fastest plane around. Thus, the "LA" complaints will go down, but they'll all be replaced by Typhoons or Fw190D-9s.
Perking the "Big Four" will not do anything.