well, you've heard wrong!
upgrading the speakers to a coaxial or 3-way speaker will DRAMATICALLY change the sound quality of your system. just because the aftermarket speakers are underpowered a little doesn't mean they won't sound better than the stock speakers....
your front speakers are the most important, in my opinion, to replace first(but I mean come on, there's only 1 other choice
). you need those highs and mids to be nice and clean so you don't just hear the rollbar speakers.
i would get the adapter brackets from MJM Auto Innov.
and put some decent 5.25"s in them. youll be blown away at how much better your jeep sounds.