Generally, supercars are stock factory models delivering above
400bhp and sprints to 60mph in less than 4 secs in a somewhat
coupe-like or chassis designed ground up with performance in mind.
If a factory makes a 4 door sedan with a super engine means they
are trying to appeal to the practical driver whom has loads of cash
to spare. It also means they have compromised pure driver's
pleasure to some form of practicality and marketability. These are
not supercars, they are superbly-marketable cars. Modded cars are
by nature in another category so we shan't discuss that.
As far as i recall, Japan has not yet produced a stock factory car
delivering such power and speed. Not any STIs, Evos, S2Ks, NSXs,
RX7s, or any other high performance sports cars in the Japanese
stable has acquired such levels of specifications until the current
GTR.
In other words, Nissan has by definition manufacured a "supercar"
by virtue of paper specifications. You and he might not consider
the GTR as a supercar, but i am sure those whom are fans do. The
first Ferrari or Lamborghini weren't supercars either, but today
they probably are due to their relentless pursuit along purist
lines of delivering the ultimate high performance road
vehicle.
I daresay that Nissan has just raised the bar on supercar
affordability by building one at such low cost. Or rather, offering
one to the mass market at such a low price. If you can build a 200
grand supercar but some other smart alec need 800 grand to make
one, who's the dumb one i wonder. Either its overpriced on brand
value, or it simply makes you wonder what the Japanese could have
included and given to consumers with a sticker price of 800 grand
for a car. Premium leather seats? You mean only Italian cows can be
made into leather? The gap is still in existence of course, but the
bridge has surely shortened.