Here are some guidelines. I didn't come up with these - they were extracted from a US Army manual on vehicle recovery.

If a vehicle is mired to where the tires and the wheels meet, you will need a pull equal to it's weight to get it out.

If a vehicle is mired to the hubs, you will need a pull equal to twice it's weight to get it out.

If a vehicle is mired to it's body, you will need a pul equal to three times it's weight to get it out.

So...load you rig up with all the gear you bring on the trail, and weigh it at a struck stop. Then do a bit of math, and decide how often you're willing to use a snatchblock.

Also understand that most winches will only pull their "rated" amount when on the last or second-last wrap (closest to the drum). As you move outward, you may find that the effective amount of pull delivered is cut down to about 70% of the "rated" pull.

So: 8000 pound rating X 70% = 5600 pounds single-line pull or 11,200 pounds double-line.

4500 pound JK Unlimited X 3 if it's really mired = 13,500 pound pull needed.

What does all of that mean? You may be all right with an 8000 pound winch...but you may not. I personally spent a few more dollars for a 9500 pound winch.

9500 pound rating X 70% = 6650 pounds single-line or 13,300 double-line.

If you don't plan on getting really stuck, an 8000 pound winch may do it...but it may also fail you when the going gets tough. There's a reason that a lot of the experienced wheelers will spend the extra money for 9500 pound winches - normally the same reason that so many of us buy Warn winches.