I was going to get the Alpine 9886 but for 100 bucks more I've been looking into the 9887. It says the crossover is adjustable from 20-200 Hz for high/low pass. How close can you select each point? 50,55,60, etc? Also is the crossover in the head unit better than a built in crossover on an amp? (Zapco Reference with 12db slope) I read about people using this h/u for an active setup, I know thats for high/low pass but not for tweeter crossover as they need crossed around 4K?