It sounds like you've torn your exhaust mainfold gasket...and yes, it's very important! I'd say that's why your engine will no longer start properly or continue to run. That's also where all of the fuel is leaking out.
If you have your vehicle owner's manual, or the manual for the engine, look up the part / part number and give your lhs a call to see if they stock that particular part.
Hope this helps!