I read somewhere that the GN's did not initially come with an intercooler, but the info I read may have been referring to the first turbo regals that came out.
IMO simply turning up the boost still leaves the car in stock form. You can easily turn down the boost to factory spec if you wanted to. The motor came with the turbo, therefore any adjustments to it is still stock in most respects. Now having a motor that is girdled with larger injectors and other aftermarket pieces, that's not stock of course.
And another thing, todays standards of cars flat out sucks. Trying to sell me on a POS maxima beating a
grand national. Either your trying to be funny or someone sold you some shitty crack. A factory maxima can possibly get a low 16 in the quarter if that.