Does your jimny have airbags? If so you need to get a bumper designed for this, i think ARB does one? A rule I read somewhere while i was researching winches was the winch should be at least 1.5 times the weight of your vehicle.
But I would take that as the very minimum, If say your vehicle weighed 1000kg, and you were stuck in bog or against a bank or rock, you now have 2000kg or more load on the winch for example.
And who says you only ever winch yourself out?
I was going to get a 6000lb winch for my Samurai, but ended up with an 8000lb. And im glad I did, ive used it about 10 or more times, but only twice have I pulled myself out. The other times were hilux, 70 series cruiser, VX cruisers, suzukis. Authough I have to be anchored to a tree or other vehicle, or ground anchor. Lan-cor - 4 x 4 Vehicle Recovery, Christchurch, New Zealand
I once had a Isuzu Bighorn and Landcruiser tied to the back bumper as anchors while winching a hilux, I pulled myself and the other 2 vehicles , thats 12 wheels locked up being dragged!
My homemade bumper