I damaged my flexpipe on nismo catback its in the shop now I'm waiting on the news on wether they can repair the mesh on it or not...but if they can't I was wondering could I put an HKS y-pipe with the nismo Catback???

 

If you didnt see my post in the other thread, a Y-Pipe is not necessary with a cat-back, since a cat-back runs from the outlet of the cat-converter all the way to the end.

 

I see what you mean now...you would have to check the diameters on the inlet of the pipe before the muffler, since having a larger diameter on the Y-Pipe outlet will hurt performance, i.e. you are shoving more gas into a smaller pipe.

 

Nismo midpipe is 3" so get a Y pipe thats 2.5" to 3" you can get a cheap Megan racing one.