Hi all sifus..another noob in ICE here, hehe.

This is my recent ICE (just upgraded 2day):

Kenwood MP4036U HU
Kenwood P605ie 6.5" component set
American Sound CS50.2 2x amp
Lightning Audio 12" Sub

My questions:

i. How to set my amp
ii. How to set my Kenwood HU, esp built-in HPF and LPF
iii. Will buying a pre-amp make my speaker sounds clearer and better?

By the way, currently my 2x amp is connected to sub. All other speakers powered by HU. Still waiting budget for 4x amp.
Pls advise.

coz bought the kenwood HU and component set earlier. Then didnt want to go for kenwood amp and woofer coz pricey and so-so only. So decided to go for Lightning Audio. But not enough budget for Lightning Audio amp, desperate too, so get average American Audio amp first. Hehe.

You can help answer my questions?