I have a 2003 G35 Sedan. I'm getting the Gruppe-S Y-Pipe, the coupe Mid-Pipe, and the HKS Sports Exhaust. I'm going to assume this is a straight bolt on installation. Is there anything else I need to know or do when I have this setup. I read something about something with different sizes from a 2.5 to 3.0 and producing a unclean flow and that you should get some type of transition piece. Any help would be appreciated. I'm going to be doing this next week.

 

Most of the aftermarky y-pipes have a 3 inch collector. The coupe midpipe's opening is rougly 2.5 inches. Although it doesn't cause a large problem, being able to go from 3 to 2.5 cleanly will help the air flow.

There have been a few posts of custom reducers made by members, or maybe contact your local muffler shop and see if they have anything.

Also, you might want to search on the coupe mid-pipe/hks exahust setup. Few have experienced a nasty drone or raspiness. Of course it might be different on every car.

I didn't see anything about a z-tube or airbox/k&n...you already have that.

thanks
mike

 

Check out this thread. Should answer your adapter questions.

https://g35driver.com/forums/showthr...light=mid-pipe