You know Trurbs, I have been into audio for 35+ years ( home and car as well as pro audio) and most anything is better than stock.
The Kicker system you are talking about should be fine but the factory radio will have a built-in eq (that you can't adjust) just for the factory speakers and may or may not sound quite like you expect it to.
It will probably sound better just because it is a set of seperates and that makes a big differance.
I am a JBL fan and highly recomend them but I am biased for sure.
JL Audio also makes some pretty darn good entry level stuff that I find hard to beat.
Sound is a very personal experience and never let anyone tell you what sounds best to you, only you can do that.