Just did a brief comparison of speeds of La7 and Spitfire XIV.
Sea level, La7 is 370 mph, XIV is 360, 10 mph advantage for La7.
3000 meters (10,000 ft), La7 is 396 mph, XIV is 405 mph, Spitfire is 9 mph faster already. At 20,000 ft the La7 is doing 418 mph, the Spitfire 424 mph, not much difference there. Above that the La7 gets slower the Spit gets faster.
Up to 3000m the La7 and 109K4 (1.8ata) seem to be nearly identical in speed, above that the K4 pulls ahead.
The Tempest on the other hand, was 376 mph @ sealevel, 409 @ 10,000 ft and 431 at 20,000 ft (early variants with 9 lbs boost, 11 lb boost Tempest was 398mph @ sealevel). It's faster than either the La7 or Spit below 20,000 ft and loses to the Spit above that.
Double post, but what the heck, been several hours since the last one! lol