as long as you order the correct size any speaker will fit, crutchfield sells a harness that connects to the factory one, i replaced all my speaker wire with a larger gauge when i did my sound system upgrade.
Dear Algebra, Please stop asking us to find your X. She's never coming back and don't ask Y.
I wouldn't even bother with the harness. Just cut the connector off and solder the wires directly to the new speaker. Less resistance.
Kicker speakers... I wouldn't buy a Kicker component set for the front but they might work as a good speaker for the back. They do produce good bass for a 6.5" (With an amp) I run Focal K2P in the sound bar. Anyone you talk to will say you can't put Focals in the sound bar but it can be done. : ) If you decide to go with something with a deeper magnet it will take some customizing. They will have to be ported as well. The end result can look stock.
Infinity... Kappa's are good, Reference (The line that you see in Best Buy, etc.) are not too great. I prefer Focal, MBQuart or Bostons.
I hear ya on that. Why spend that much on a sound system for a jeep when the acoustics are bad anyway. And could get stolen easy. Bostons and MB's are pretty expensive at your local stereo shops but you can get them online pretty cheap. Boston SX60 set (fits Jeep) runs about 3-400 retail but can be bought through wholesaler for about 125-150. I like Kappa perfects too! Good speakers