Are aftermarket struts/shocks (ex. kyb, blisten,etc) shorter than OEM ones? Was wondering cuz theoretically then, aftermarket struts paired with a 1"-2" lowering spring (ex. prokit, neuspeed,etc) would yield an overall 3"-ish drop. Am I right?

 

No, the spring is setting the height (or drop). The struts are shortened on the piston so that they won't bottom out with shorter springs.

Not all aftermarket struts are shortened, for example:
Biltsein HD's and Bilstein Sports-same shock but the sport one has the shorter piston rod.

 

Changing the shocks will not change the ride height, unless you were using Koni Yellows and used a lower snap ring position for the spring cup to sit on. The shaft is still the same length as OEM.

And 3" is way too low for an Integra, unless you want to be scraping ants off the road.