My apexi n1 evolution came with just one gasket. (Assuming the one that connects to the Y pipe)

Do I need one that connects the straight pipe down to the muffler? Or can I just bolt directly on?

 

use a gasket w/ gasket sealer. otherwise u get leaks, which causes unwanted noise, and possibly loss of power. spend another $5 and get a gasket from nissan. although, make sure u get the right size. it uses 3 different sizes. a 3 hole gasket 4 the headers/cats (up top) 2 small gaskets where the y pipe hits the cats, and a larger gasket where the y pipe gets the mid pipe.

 

This is a cat back, so I dont need to worry about anything from the ypipe up. All I have is the midpipe goes back to the muffler.