My 1997 Saturn SL1 exhaust smells like rotten

More than likely, you have too rich a mixture in your exhaust. When your catalytic converter is taxed by too much unburned gas flowing through your engine, the fumes coming out your exhaust pipe smell like rotten eggs. The smell itself is sulfur based but shouldn't be too much of a problem in itself. Check the inside of the tailpipe with your finger. If it's black and sooty, then you could think about having the fuel injection checked out, other than that I wouldn't worry too much as long as it runs decently...

replace your catalytic convertor. you can go to a smog shop and have them perform a "cat efficiency test" and see what they tell you or simply go to a muffler shop have them install one.