I have horror stories about my ex's exploits at the oil change store (concerning her car) but they pale in comparison to this next one.
An acquaintance of mine took his 1978 Fiat 124 spyder into the local oil emporium. (Lovely cars these, and should be saved!)
He got it back and drove it that day until the transmission unexpectedly ground itself to a pulp. I don't remember how many miles, but it wasn't too many. The same day. He complained about a lack of power.
In checking out the car, he checked the engine dipstick for no other reason than he needed to do something in his distressed state... Well sir, it had plenty of oil in it-after all, it had just been changed. Oh yeah, it had pleeenty of oil in it.
To keep it short, the lads had pulled the readily accesible drain plug to the transmission, drained it, and "refilled" the engine.
I am surprised the engine ran at all with 12 quarts of oil in it!
If you can find a good indy, you are in. Find someone who works out of his house and is not rushed. I knew a guy who speciallized in Ferraris, tuning and maintenance only. And he wouldn't be rushed. If you couldn't leave you Ferrari with him for a week, along with a $1000-
Take it the lads at K-Mart! They need to learn on something!