Not to worry, you said they installed a new exhaust system, what you are are smelling is the burnoff of what is all over the system, grease from the mechanic handling the parts, factory residue from manufacturing etc, you will need to drive it a while to burn everything off, take a nice sunday drive and it should all burn off

__________________
Jerry

2004 SL500 Black 55K Miles
2002 s500 Black 90K Miles
1986 300E Gold 233K Miles
1966 Twin Cessna 320D
1989 Jeep Cherokee 233K Miles
1994 Ford Van E150 399K Miles