i dont know your skill or experience but im guessing you cant do this
neither can i....

someone with experience and many years of practice did this
professional

a lot of fabrication, welding, shaving, and sanding is my guess

I Probably wouldn't ivest in that as its too much money, its not HORRIBLE, its rather unique. I must say that looks pretty crazy, a real head turner.
But ill be fine with my 89 taillights they looks better since it fills the whole back on the car, just perhaps to darken them a bit would be nice aswell.

my rendition on the swap
 

1989 mk3 (in process on throwing on my new turbo and shes back on the road) also notice i shaved the trim panel that wraps around the car...lemme know what u think, i think it looks good, oh ya... the trunk key lock in the lights is functional :)

look at my above post..im 19, got the car when 16, and i have been workin on it ever since....it only took me about a year and much trial and error.