Anyone know if I can change the spring out for a stiffer one if I ever choose to do so? Just curious.

 

I do believe Tein can offer a stiffer spring. They won't go any higher than 2 kgf/mm stiffer than the stock setting. For the 4th gen Maxima they are set at 7.0 up front and 6.0 in the rear. Tein will charge $50 additional per spring.