imo if a shop is handling you car and breaks it they should be willing to help you out at the least..even if its just figurin out what was wrong and who truly is liable for the cause..if the motor was improperly built..if they were tuning and not feeding enough fuel whatever the cause may be just help diagnose it and if they are at fault fix it..but a shop that threatens someone is no one to do business with....from your experience i can tell you i wont ever go there...