As a point of clarity. The 2.4L is a good engine so don't sweat it too much. Also are you a Stick or Auto Trans?
Most of the engines that are used in Jeeps are designed to build good low end torque. So any horse power aid by way of better air flow, be it intake or exhaust will help. The platform was just not intended to be a very strong performer at highway speeds. I would get the ole girl look'en the way you want (I can totally see what your shooting for) and see how she does as a daily driver. Just keep in mind anything you can do to decrease or limit weight is to your advantage. If the power is not there or fuel consumption is in the toilet then see what you can do to fine tune the 2.4L or address the gear ratio your running.
My 4.2L inline 6 will leap of the line at a light (thats the torque talk'en). I have even caught a few ricers and such off guard, but by the time we blow past the cross walk on the other side its all over. I am geared to run the wheels and such for off road. My top speed right now is about 55 mph 60 if I really make the poor boy scream. I need a 5 speed transmission. Thats my current project, what a mess
My point is not that you could ever do anything to win a light to light showdown and I know that is not your goal. Yet working within the power that you have will make the Jeep more fun to drive as well as more affordable.