I'm looking at staying with the stock rear section of the exhaust, but running Nismo headers and Y-pipe. I'm going back and forth on cats, as I hate to run into a lean problem or anything else that's going to turn a new, reliable car into a finicky, borderline basket-case. (Too many mods on a '97 Mitsu. GSX has led me to my current stance. )

At the same rate, I'd hate to only get an increase in sound (for the money) by leaving the restrictive stock cats in place.

So, assuming I opt for cats in addition to my headers and Y-pipe, what else should I need to make the most of this combo? A reducer pipe from the Y-pipe exit to the rear-section entrance, perhaps?

On the intake side, I'm sticking with just a UT G-Tube and a hi-flow drop-in filter... ...for a while.

And suggestions on making the most of this exhaust combo?

It was my understanding that the Nismo Y-pipe was only offered w/ the full exhaust system. Were you going to get a different brand Y-pipe?

Nope. I went through Performance Nissan at www.mynismo.com. I have the headers and Y-pipe sitting behind me in my office right (just no car yet ). And judging from pics, it does look like the Fujitsubo Y-pipe, only with a metal Nismo badge welded to it. Not certain, but it appears to me to be the same.

The headers look good... ...even if they are just sitting in the box.

Took measurements, and the Y-pipe exit looks to be a 3".

What part of TX are you from?

**IMHO**

putting headers on the car and not replacing the cats...not worth the $1k+ you paid for the NISMOs.

The gains/bennies from your intake / exhaust is the sum of all the mods together. If you breathe great up front, but "plug" the rear, it's probably not worth it.

If you are going to consider a plenum in the future, then you mind as well consider an ECU flash to clean up any A/F issues.

Good luck... cheers, Ted

Moog - West Texas... ...San Angelo.

Ted - That was my concern with NOT doing the cats. I find myself leaning toward them a little more each day.

The reason I'm not going to replace the rear section is that the consensus seems to be that the rear section has adequate flow for a NA VQ. Granted, it will not ultimately flow as much as a larger system, but it should do fine with such minor mods. Also, I believe the back-pressure of the stock rear section might be beneficial in the lower RPM range, without being too restrictive in the upper RPM range.

Initially, I wanted the headers and Y-pipe mainly for improved sound quality, with the hp increase being a bonus (in terms of bang-for-the-buck). Of course, now I'm wanting to go for the cats to maximize that gain. Just wanting to maximize the combo I'llm be running.

As for the intake side, shouldn't a hi-flow filter and G-tube provide enough extra flow to see some gains from the headers and Y-pipe? Granted, the gains will not be as high as if I opened up the intake side with a bigger plenum or spacer, but certainly it's not a completely wasted effort.

And I realize throwing a larger plenum into the mix will call for an ECU reflash, which is why I'm waiting a while to make those changes.

I am not sure how much of a sound change you would get only changing out the headers and the Y-Pipe without also changing the cats. Anyone have any experience?

That's why I specified sound quality instead of sound quantity. lol

In my experience, an exhaust note has a better quality when it's traveling through nice, aftermarket SS pipes, compared with the stock mild steel pipes. I know it's a subtle difference to some, but I'm sure some audiophiles understand spending for what others might consider small gains in sound qaulity.

I'm not into stereos that much. If the stock sound system sucks, I'll turn it down and listen to the engine note.