It doesnt matter what size the wing is, what matters is the chord length of the wing and the angle of attack it's being used at... Most of the 'tuner' wings available to the market these days do absolutely jack all... apart from give the drivers an ego boost (for what reason i dont know...)
Unless the plane of the wing is large enough to enable the correct boundary layer actions, the wing is simply a drag inducer, an air bulldozer, producing very little downforce for the drag it's generating....
From the sounds of it, they wings will be available on cars which have been fitted with them in Japan, not the US or Aust or UK, which realistically will mean they should be on high hp RW, MR and RR cars.
The intellectual which stated that wings only work in triple figures, you obviously have never watched any form of F1 racing, note the difficulty of drivers to turn into slow corners after they have ripped their front wings off.... monaco is the ultimate example my fiend...
I'll give you an example of a car designed to run up to about 80mph or 120kph, noting that it IS aero limited, but at 80 kph its already providing over 120 kg downforce on the rear wheels, which with this car, would make it an awesome car to drive around any mini track in the GT series...
Note: this is a slow speed wing, hence its size, but it follows many key principles used by aerodynamists to increase the power of the wings without going to large.. ps the entire wing assemblies weigh less than 12 kg, front and rear ...
mmmm carbon fibre honeycomb composites.....