Could be a number of things if they replaced the front sway bar. Since the entire subframe must be dropped to do that.
Ask them if they used the proper tools to align it when they put the subframe (with engine & tranny on it) back up???
They could have damaged a strut.
Swaybar endlinks.
Axleshafts.
A number of things in the front could have been damaged or misaligned when doing a job of that nature. I would take it back and demand satisfaction!
