You cant do network from the headunit, but if you have a 4 channel amp for the fronts, you can separate the tweets and mids that way, or by using an external 3 way crossover and a 2 channel amp for each set and 1-2 channel for sub.
Most coaxials will never sound as good as a component set simply for the crossover quality. Now, there are some that are more like a component in that they are bi-ampable or have the tweeter wired separately from the mid with a proper crossover or external crossover. Kicker, Focal and a few others sell "coaxials" for use where space is limited, but are wired and sound like components. Some components are also "convertible" in that there is a phase plug that you can unscrew and screw in the tweeter sending the wires through the magnet and out the back side. Not sure who had them first, but Kicker has been selling them that way since the silver coned Resolution series that came out after the black paper coned ones.
Sorry, missed the last bit, YES, it will sound that much different using a 5 channel like that. When i first got an active crossover in my 90 Eagle Talon 20 years ago, i could not believe how much more musical my music sounded. And ive been a musician most my life and an audio engineer for slightly less than that. Its a night and day difference in a "normal" setup, meaning im sure there are some high end systems with passive crossovers that will blow your mind.