Years ago I tried to straighten my rear bumper (lady rear-ended my Dakota) using a cheap come-along from the hardware store. Wasn't working, so I made a cheater out of two eight foot 2 by 4s screwed together with some blocks... what could go wrong? The come-along basically crumpled into scrap metal. The 16.5 k winch I have, that is mounted on a custom bumper fabbed out of nearly 1/4 in. steel, and mounted on the F-350 I now have would probably be able to straighten a bumper, but I would never do that! The same winch tore a 12 in. diameter limb off an oak, but that is another story (I was not trying to do that -- had a block hung on it).
Heavily loading a system that has components with unknown limits is a really bad idea. Everyone has seen vids of people trying to yank a stuck vehicle out of the mud with a beefy 4 by 4, and just pulling off the bumper! Still feel guilty about returning the "defective" come-along for a replacement, but I have spent thousands at that same store since then. And it was a cheaply made tool, but could shoulda read what the load capacity was and thought about that for a bit.