$3000 sounds low...$11,000 sounds like someone has been huffing too much paint fumes.....
$5000 for a NICE,
quality paint job is fair, and it really should take a month, at least, unless it is a shop that does NOT do insurance work.
As far as YOU being responsible for parts that THEY break? You gotta be kiddin....."Run, Forest....RUUUUN!!!!"
Granted, taking 20 year old(or older) urethane bumper covers off is a sure bet for something cracking, and bolts twisting off, but still....that should be expected, and figured into the estimate....not added on after the fact.
When I had my '74 painted in '97, I wanted a guy I know does top notch work to do it, but he wanted $5000, and it would take 6 months. I couldn't pay that at the time, so I went with another shop that was recommended by some of the local club guys. Biggest GD mistake I have made on that car. He did it for $3000......EIGHT friggin times.

I finally decided enough was enough, and just accepted that it was as good as they were gonna do it.
If you are willing to do a lot of the grunt work, like removing trim, the interior, and stuff like that, you can definitely save a little labor charge. But I would certainly do some homework, and ask around for recommendations, along with asking to see some of their work. A good shop will not have a problem doing that.
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Joel Adams
My Link

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"Money can't buy happiness -- but somehow it's more comforting to cry in a CORVETTE than in a Kia"