Take a newly made (read still tight) MKIV made with a new rig, foils and the current layout and you would be hard pressed to see much if any significant performance gap.
Sorry Matt but I disagree strongly here as do the majority of A Class sailors. The difference between the MkIV Boyer and the Flyer when it first came out was significant. They are now saying it is a simular leap to the DNA. They became the must have boat because you needed it to compete at the pointy end.
Even the difference in the Multi Manufactuer OD class, Tornado the difference between the Reg White and the Marstroms were significant. I have done a fair bit of racing on the Reggies and Marstroms and can confirm they are chalk and cheese. Made me wonder why we tried to pursue for so long on a Reggie kitted out with all Marstom boards, beams, stick.
When the level of competition increases, the difference in equiptment becomes quiet noticeable.