I just did my 6x9s last weekend. I installed Kenwood’s, they are really nice but they ran me $110 locally. Installation is the exact opposite of easy, I just had to warn you Colon J Unless tearing out most of the back half of the interior of your car. Then taking a jigsaw to the speaker mounts to make the new speakers fit. Then re-assemble everything, and finish by splicing wires while laying in your trunk is easy. Well, maybe it was easy. lol
The only easy way to do the rear speakers is have a buddy help you, who has actually done this on a GP before. Its not “hard“, just one of those things were if you haven’t done it before it is a head shaker.
Just to minimize the flame-age, I put some new speakers in the back of an old Accord I had, just had to pop out the old and plug in the new. No interior removal, no splicing new connections. EASY
I’ll keep an eye on the posts if you run into issues. Good Luck