I searched through 14 pages of posts on GTSPEC. I found an old thread form 2008. I want to know if everyone is still in agreement.
I want to stiffen up the chassis and want to add GTSPEC braces starting with the most effective brace first. I've already got coilovers set to full stiff and sway bars. GTSPEC-MARK created the below list in 2008. Thanks for the help!

1. Rear M Shape Brace + Rear 2 Point Tie Brace
This will be the first 2 brace to get. These two braces tie the lateral arm and control arm together. These two braces act almost like a sway bar. We have tested the same braces on 350Z and the most effective brace so far.

2. Rear 6 point subframe brace
Because it's a bit pricey, that's why I list this brace as #2. If budget allow, this brace is a great addition. The brace link the rear subframe to the chassis. It added three extra reinforcement points per side. It's a 5 piece kit thus a higher price than rest of the braces.

3. Fender Brace
Fender brace ties the front engine compartment to your mid chassis. Known to be used on many track car, it provided extra reinforcement for the front of your car.

4. Front subframe tie brace 2/4 point.
I list this lower than the rest mainly because the front subframe are already very stiff. These two braces reinforce the existing mounting points. It still provide added reinforcement but not as much advantage compare to the rest of the braces.

5. Front subframe left + right tie brace
This brace is the last on the list because it's a significantly smaller brace compare to the rest. However, it does added two extra reinforcement points to the front subframe, but compare to the rest of the braces that's available, this brace has less effect.

6. There was not any mention of the Front Strut Brace. Is this because it's not effective or did it come out after 2008?

 

I've heard and read that the fender braces do close to nothing...

 

Lol, that's a good thing because I'm definitely not pulling off my fenders.

 

Fender braces should not be put on unless you're tracking the car. Our cars are designed and engineered specifically to safety standards to provide you the most protection as possible. Normally in a hard front end collision, the front of the car will "crumble" upon impact. The fender braces will comprise the way our cars absorb impact, thus comprising your safety.

 

i got the m-shape FS. hit me up!
i actually really did like the bar though.

i really did like my #5 front left and right tie brace. but i can't really compare it to 2 or 3 which i dont have

 

I have all bracing except the tower brace because of fitment issues I've read on the forum.The handling of the car is exceptional now with Hotchkis sways and Michlein Pilot Super Sports.I kept the stock springs and ride height.I'm extremly happy with this set up.I'd like to know if GT Spec has solved the fitment issues of the strut tower brace, I've read it rubs on the under hood and insulation.

 

I have four of them for sale if you're interested in buying used.

 

I bought a few of the GTSPEC braces recently. They make a very noticeable difference with handling with my current suspension setup. I've got Powertrix coil over suspension set at the most firm damping and front/rear Hotchkis Sway Bars. I've got the following GTSPEC braces:
6 Point Rear Subframe Brace
Rear Tie Bar
Front 4 Point Ladder Brace
Front 2 Point Subframe Brace
Front Subframe Tie Brace (L+R)

 

So...I installed the rear lower lateral and lower tie braces today on my '12 G37x sedan. The car is much more planted around turns and the body roll is greatly reduced. I am waiting on the brackets for my G37s rear sway I have sitting here waiting to be put on. I am getting the feeling it wasn't the best idea to install these before putting on the thicker/stiffer bar, but I wanted to see what difference these braces make alone. It feels as if the back end of the car is unstable when going over bumpy roads/pot holes, but not in the way my friend's 370z is, which is due to it's much tighter suspension. Something just doesn't feel right. Maybe this will be fixed once the upgraded sway bar is on. Maybe someone here can provide some input. Other than that, the handing capabilities are definitely enhanced. I saw on the FX forum that someone mentioned installing these braces with the tires on the ground to prevent misalignment, but then I called GTSPEC and they said it didn't matter. I hope installing while on a lift didn't cause any issues. I may get the alignment checked anyway after I install the rear sway bar. I am good with all maintenance projects, but this one is new to me. Hope to hear some feedback. Thanks guys and GTSPEC for the awesome and light braces

 

UPDATE: The alignment was way off. *Be sure to install the rear braces with the wheels on the ground.* After spirited driving with the alignment fixed, I could more accurately test these braces. There is NO MORE BODY ROLL which is a problem with the stock G37x sedan. I am hoping it's not too stiff after the G37s rear sway install. If you have interest in these braces, I can attest you will not be disappointed and I am glad I followed the advice in the OP.