You have missed th epoint that some ppl like to ice up (or do up) a car that they have or just want to be differnet.
Maybe they don't wanna spend money on performance but want a cheap stand out car.
Remember, some ppl have no clues. haha
I know of people who have turbo'd non turbo cars, only to gain 190kw at the front wheels - pointless IMO, but they love it.
Truth be known, the 50k spent on it could buy you a very good R33 GTR example.
Horses for courses I guess. The orld would be boring if every man and his dog poured $ into Skylines - even though these are my preferred fun car.