Anyone have good luck with the USPS finding their lost auto parts in the system?

Nope.
Where did you come up with a low dollar figure like that anyway?
A lot more than that.
On top of that, there's the 23 bucks that i paid for priority mail shipping that i lost out on also.
So, how much were they - $100? 200? My point was, it likely isn't worth the headache of dealing with an agency like USPS over. How much is your sanity worth?? Chalk it up as a loss.