I got the speakers in last week but was traveling so I just got to the install today. I will say to Clark that while they did fit, it was not exact. I had a little trouble getting them in and they are not flush mounted as the stock speakers were. However, it is not obtrusive to me. I installed the Speakers and the Grills that came with the Polk Audio DB651s. I took some pictures while installing and loaded them up in the Gallery. You can search the gallery for my name or for "Replace Rear Speakers in 04 TJ" and you can find them all.
Difference between stock speakers and DB651:
First, I found after trying to install with the pod attached to the roll bar, that it was much more difficult working upside down. So if you are going to do this, take the pods off and work on the ground. Much easier and quicker.
Remove the speaker by taking out the 4 #1 Phillips Screws. With the factory speakers they have a harness that clicks into the speaker. I cut that out, leaving just the wire, not the connector, crimped on a quick connect to attach to the new Polks. One for each post (+ and -). You could just spot weld the wires to the terminal, but I don't see the need myself and this is still a clean way to do it. I can also remove this and reattach the original speakers, should I ever trade this in.
To attach the speakers to the pods, I used the original screws that came out of the stock speakers to set the first screw in place. Since I was going to use the Polk Grill, I left the other 3 original mounting holes empty and used the other screw holes in the speaker to screw into the pod. For this, I used the screws that came with the DB651s (self tapping) to screw in 3 other holes, not the original mounting holes though. Then after getting the speaker in, I set the Polk Grill on top of the 4 original holes and with the 3 remaining holes not used, I screwed the grill into place.
Here is the look post install from the Top down.
Here is a look post install from the side to show how much the grill will stick up.
After this, just reattach the pods into the jeep. My finished look is as follows:
More pictures in the Gallery if you are interested. Thanks to KentClark for the reassurance that they would fit. I suppose as they say your mileage may vary but this was not an exact fit as KentClark said but it looks great to me and sounds much better!