Ren i wasn't advocating the spit V for the la7, but rather the spit V for the spit IX. At MA alts the spit V out classess the spit IX, at sea level the spit V has +16 boost, the spit IX only +15. The spit V is only a couple of mph slower than the spit IX on the deck, increasing to 7mph slower at 10k. It wouldn't surprise me if the Spit V has better acceleration than the spit IX- I've no idea if that has been tested in AHII.
As i said before, i can't imagine la7 pilots switching to any spit. They would probably devide themselves up into the other late '44 fighters.