its not their work that is the issue, its the owner and his customer service that is the issue, he sometimes like to change prices, and he knows when he's got you by the balls.
be serious when it comes to negotiation and get a price on any-parts before they start the work.
the maxican workers know their crown vics very well, I'm a full service tech at a shop, and besides me, they are the only ones to touch my car.
I honestly think it's a cultural thing.
When I was there getting my push bumper, I offered the owner some beef jerky.. Real beef jerky, the expensive type... He took half of it... Then turned around and said 'Give me some more so I can take it to that guy' (The Mexican that was working)....... Then, we found out about my electronics expertise, he says 'oh good, you can tell me how much this stuff is worth, follow me'...... then drags me back into the depths of the panther junkyard, and says 'here, you write down what these are worth'..... Didn't ask me, didn't offer a discount for helping me out, just straight out told me to do it, like I was his employee...
Like I said, I think it's a cultural thing.