Just went through all this myself... I have the SXT Ralleye with 8.4" touchscreen, 6-speaker, bla bla bla. Thought it sounded OK, but very weak, needed a little more bottom, stronger mids, not so shrill highs, (what you would expect from a "better" speaker). I don't want to vibrate my neighbors out of their beds or to shatter their picture window as I go by, just wanted better sound. Went on e-bay, (yes, e-bay), ordered the Kicker upgrades, (actually from Chrysler Dealerships!), plug n play! I actually ended up getting one for a Ram Pickup, 6 X 9 mid bass, 3 1/2" speaker for the dash, picked up 2 sets thinking that I'd fill the holes in the rear shelf... Ran approx. $130/each kit. Much to my surprise, the wiring is NOT there in the rear shelf! Easy enough to remedy, tap off the rear door speakers... Also purchased a Kicker Hideaway 11HS8 powered subwoofer, mounted to the left side of the trunk right behind the seat. I then bought a Clarion XC1410 Amp, 50 Watts /channel X4. $260/ speakers, $250 / Kicker 11HS8, (there are cheaper ones), $129 /Clarion Amp... about $650 for everything, (wiring kits, etc.)... Then, my time to take the dash apart, glovebox, doors, rear shelf, etc., not really hard, but time consuming.
It's not going to shatter the windows in the car, but it sounds MUCH better than it did with the original cheapy speakers. Can't say how it would compare to the Alpine setup, but I'm very happy!
The caveat here is you need to be handy, and have the tools to do it Not really all that tuff once you get going.