Nightshade V.2's can take a decent amount of power butt idk about that much lol. I would run a SAZ-4500d or equivalent power to each sub If I end up going all out which it a MAJOR possibility. Is there a possibility of changing subs? Yes, I could change subs but I live like 10 mins from sundown so it is very convenient for me to pick up my subs + I already have 1 18. I could do 3 18's but my port would have to be over the subs all the way across which seems a bit unorthodox to me. I could also do 4 15's.... Then it just comes down to the cost of things lol. (2) 21" drivers would be amazing