I haven't seen one of these anywhere so I'm going to give it a shot for the community!
QUICK DISCLAIMER: I AM NOT PAID OR PARTNERING WITH IIR OR ISR - THIS IS MY TOTAL HONEST REVIEW AND PICTURES POSTED FOR THE COMMUNITY!
As of 2/14/21, I just received my headers and will provide an initial review along with detailed pics and measurements for anyone looking to possibly purchase these. The pics you see online are either sparse, or outdated versions.

OVERVIEW
I bought these from Import Image Racing, and they came in just a few days. Best price and free shipping. IIR lists it as only fitting 2003-2007 Gs, however CZP lists the same headers with the same part number (IS-SSHD-VQ35) as fitting for every model of G/Z, and I personally know 2 people running these headers on G37 sedans, one of them being RWD and the other being AWD.

INITIAL REVIEW
The packaging itself is very nice and secure. Gaskets are all included together in one bag along with hardware necessary to attach to the Y-pipe. Although I don't think i'll be using these gaskets. They look like thin metal sheets layered, and the tack-welded spots on them protrude a fair amount, enough to steer me away from using. I am going to purchase a new OEM one for each head. The welds look good, and the headers feel good. They aren't too heavy, definitely weigh less than OEM cats and manifolds combo. The Y-pipe opening where headers connect also isn't 2.5", it is about 2.35" or so. Not a big deal, just additional info I realized.
Another weird thing, my set had pieces of the plastic that they come wrapped in stuck between the runners. I'm not sure how it even got there but it's there lol. Will try to remove it with fishing line.






The actual headers themselves look amazing, especially for $580 SHIPPED TO YOUR DOOR.

The welds look very good for the most part. There are some places such as the collector where the welds are black and blemished, and look a bit messy. I will leak test this set using my 5hp shop vac and update this post


The flanges are all VERY thick. Head flange seems to be a bit thicker than the 2 bolt flange below.


Some people have also reported that the quality of the welds inside each runner opening may be very uneven and raised. I have experienced no such issue. And I even have pics of the collector!!





O2 sensor ports all come with plugs screwed in, however, no extension wire for HR/VHR applications!! Downstream port has tiny hole to help prevent CEL. It is also raised higher than the upstream port.

OVERALL,
I am very impressed with what you get for the money with these headers. I have never held or even seen the high caliber headers such as PPE personally, however given the price I think these are an amazing buy. I will continue to update this thread once I install these in the next couple of weeks as well.

 

2/15/21 - More pics just for fun

Raised tack welds on 2-bolt gasket

Y-pipe hardware



Clean welds neighboring the blemished looking welds between runners.

Y-pipe opening

Other collector, with inner welds shown.



You can see the plastic between each runner!! No clue how that got there!

 

They look very nice! Thanks for taking the time to post all those pictures.

I don't mean to be critical, but, isn't this more of an "unboxing" than a review?
I was looking forward to see how they fit and sound
When are they getting installed?

 

Good thread, OP.

Patience, Sonic... Sheesh.

 

I like the design but not sure if I would ever be willing to run the VQ without cats. In for more updates!

 

Yes that is a much better way to put it - for now! I'm going to be doing a DIY install of these headers once the weather warms up. In NY it gets below freezing everyday and I don't have a garage space to install these. I will continue to update this thread once I install them and have them on my car for a few weeks, along with dyno results!

 

The VQ with no cats smells horrible. I currently have Berk Res. test pipes. Maybe it's just NYC fuel, but at a stop light you can't smell much. However, if I were to go around back to the trunk, or even just walk behind my car, I smell like fuel for the next few hours. All of my clothes, my hair, everything. It is definitely something you either learn to live with, or don't do at all lol.

 

Do you have any updates as far as fitment etc?

 

I haven't had the chance to install them yet, I have some more general prep and maintenance to take care of. I will update this thread when I do anything else with the headers!!

 

I'm looking forward to your post about the sound and difficulty of install. I plan on replacing my berk hfc with PPE headers in the near future due to check engine light issue and rusted manifold.

 

Any word on install? I have been on the fence about these, I am thinking of upgrading from kinetix hfc to these headers. They look like pretty damn good quality for the cost.

 

5 months later and I look forward to a review... How is that for patience, Rochester

 

The patience of Job, Sonic.

OP was on the forum a week ago, maybe he'll get this bump.

 

Didn't mean to leave y'all hanging. I should have maybe listed this as an unboxing Lol. So the quality of these headers is amazing. If you install yourself it is worth it over any test pipes. Sound wise, I don't have any clips, but I stopped caring about rasp so much. I have a HBP single exit with resonated y pipe, mid pipe, and a helmholtz resonator on the rear muffler. It is still extremely loud and definitely has drone. I'm FBO on FlexFuel. You can check it out on my instagram page @justanotherg37. An observation I made is that the car rasps and drones noticeably more on E85 vs 93. Side note, made 330whp AWD unopened motor.
IN TERMS OF INSTALLATION:
I installed this on an AWD VHR sedan and it fits perfectly, even though ISR advertises these for VQ35DE only.
What you need for installation:
- OEM exhaust studs and nuts (old ones can get stuck on the nuts, just have them in case they strip or whatever the case may be.
- OEM manifold gaskets - i would not reuse the old one and definitely not use the spot welded ISR provided one. OEM Nissan gaskets always worked best for me. However, I did find that Rockauto has a decent feeling steel gasket, which i will be using once I return this car back to stock. Just make sure it is multi-layer steel as well!
- E-Torx sockets ; to thread the studs into the motor
- Penetrating fluid (mostly for the steering column but helps with heat shield bolts as well)
- Flexible ratcheting wrenches - the space is very tight and you will only be able to tighten some of the nuts a few clicks at a time with extremely limited space.
- Primary O2 sensor extension from Nisformance - this is REQUIRED, mine was a type 1, however it is different for everyone so check on your o2 sensor connectors on the rear of either valve covers to verify!!

Other than that, I also did some testing of ceramic-paint from VHT and it actually made the pipe itself WAY hotter, and I also tested radiant heat in a homemade brick insulated environment to simulate an engine bay, and 2 soda cans to capture radiant heat. The coated pipe actually had more radiant heat, so I would heavily advise against it. I left the headers completely raw with no exhaust wrap as well, hasn't affected anything since I installed it in Spring 2021, and I have a specialty z flex fuel sensor that has been left without any additional heat protection that has no damage to it whatsoever.
The install is the same for AWD and RWD and this is the video I used for install. Best of luck!

Any other questions, feel free to reply.

 

any problems with CEL? i cant seem to keep mine off got oem o2 sensors changed the fuse out from the fuse box cus it was out.
CEL turned off drove home about 15-20miles parked the car for the remainder of the day , next day went for some breakfast drove about 2-3 miles CEL came right back on.