It's not clear that the NISMO is heavier. In fact, it may be lighter than the Base MT + Sport, or Touring MT + Sport. According to
this article a Touring MT + Sport is at 3,373 lbs (3,278 + 95). This would make the sport package about 95 lbs. If so, a Base MT + SP would weigh 3,327 (3,232 +95). The NISMO is listed by Nissan at 3,300 lbs.