Here are a few tips for those DIY'ers out there about the Injen exhaust installation. It's pretty easy to do but the Injen instructions can be a bit confusing at times. Anyway, hope these pics help.

I started by removing the 14mm nuts from the catalytic converter flanges as shown here. This allowed for some play in the system when removing the rear components.

 

Next remove the 14mm nuts from the flange at the rear of the factory y pipe. You'll have to use a longer socket or a wrench for this because the bolts are too long for a standard socket.

 

Now remove the 14mm bolts from the stock muffler flange. Once again, use a wrench or a longer socket. There's three bolts as the exhaust ground wire lives between the two closest to the rear of the car.

 

Now you should have enough play in the system to remove the factory y-pipe and the connecting pipe containing the factory resonator.
Next remove the stock muffler. This was the most difficult part of the install for me. The muffler hangs by 3 rubber exhaust hangers. You can remove the single hanger toward the front of the car by removing the bolt holding the hanger in place. You will have to move this hanger to a different position to hang the passenger side SES pipe (pics to follow). The two hangers in the rear are a different story. They are extremely difficlult to remove. Do what you have to do, but realize that if you cut them you cannot buy these at autozone. They are specific to the 350z and must be ordered from nissan.
Here's where they're located:

 

Now you can start installing your new exhaust. Start by placing stock hanger you removed in the last step in the new position right above the sway bar on the passenger side using the bolt and prong provided by injen in your kit with a 12mm wrench.

 

Now just start hanging your new parts starting at the cats, align the flanges, tighten the nuts and hang the exhaust in the factory exhaust hangers.

 

Now just start hanging the new exhaust components from the cats and work your way back. The flange connections marked by the red arrows can be used to adjust the system because you want 6-10 mm space between the brace and the pipe (green arrows). Also allow 6-10 mm distance between the resonators. The blue arrows just signify the two proximal exhaust hangers.

 

Hang the two cans by the rear exhaust hangers. To make the job easier I attached the hanger to the SES first and then just slid it over the factory attachment.

 

Finally, attach the ground wire and give your exhaust a good wipe down. If it gets hot all the grease and fingerprint will be very difficult to get off.

 

And now for some pics of the completed install

 

I'll have some sound clips for you all as soon as my buddy gets here with his lap top.

 

This is one really good post. thnx for the helpful pics and instructions because i soon will be getting my injen exhaust. oh and how does it sound xZlr8

 

It sounds great IMO. Now that i've driven it a bit it seems to have gotten a little louder and deeper. Down low in the RPM's it is significanly louder than stock and infinitely deeper. As you pass 3000 RPM it mellows out a bit and just has an exotic scream about it. I put the silencers in just to test them but quickly removed them.

 

Does the right one come out at a different angle than the left? Or is it the angle of the camera? If you drive with the windows up, does it have an irritable drone? I just ordered yesterday, and hoping I made the right decision. Thanks

 

They come out at the same angles...i mean, there may be a couple mm difference but it's hard to tell. At highway speed there is not a drone.

 

Great write up xZlr8. Makes the CAI much more audible doesn't it? Now just don't go screaming all over town so the cops hear you .

 

What is the diameter of the tips?

 

It makes the CAI sound awesome!! I guess that's just from the car breathing a lot better.

 

4 inch tips.

 

Thanks for the very helpful information xZlr8. I am ordering the the intake/exhaust combo package from Coz tomorrow. What type of gains did you notice?