I'm putting back on the Fit's stock exhaust but I can't remember if there is a gasket between the muffler and the b-pipe. So, two questions:

1) is there a gasket between these two parts?

2) if there is a gasket, could I run the car without it ? Or is that just stupid?

 

its called a donut gasket. it looks like a metal donut
your exhaust would not fit properly if it wasnt in there. you should get under there and check for exhaust leaks anyway.

 

You could run the car without it while you drive down to your local dealer to get one, no really your connection bolts may not be able to be tightened all the way but some people are running with no muffler with no ill effects.

Look on your old muffler parts the gaskets are hard to see and getting them off is not easy so the one you are missing may be stuck on your old parts.