Well, in 1943 the Series-5 fighters were beter than anything at the time. The Fiat G.56 with the DB-603 would have been great, and although never built, the Re-2006 could have been similarly great. Ok these planes are not up to Ta-152 standards, but I think that given 2 more years of design and development at the same rate they were going at in 1943 they could have had some truly great fighters around.