what did they do to repair the misfires? i guess, you do not know the codes that they had pulled from the car? I had similar issue on E53, N62 engine... cylinder 5 was misfiring, creating some havoc in driving, power loss, uneven idle... pulled the codes - you have to read the codes and "between the lines", as sometimes one code is saying one thing but pointing to another...

mine were misfire cylinder 5, misfire on coil cylinder 5, misfire several cylinders... I got a bosch coil for $35, swapped it - issue is resolved...

i was worried that there were some other coils acting up, but nothing else...