I'm sure you'll notice a big difference. Let us know in any case. Good luck.
By the way, when installing the JLs make sure to line up the speaker mounting holes over the two car mounting holes carefully so that you tear away the right mounting tabs from the speakers. You'll be very unhappy if you tear off the wrong strips!
And if you splice the wires be sure you connect them correctly so that the speakers are in phase. Otherwise, your bass response in particular will suffer and the soundstage will lose definition.
See note 129, below.