Finally, AMR Engineering came through with coilovers that are specifically designed for the G37x and so the wait is now over. This is my first review so take it easy on me. Many people have hard time bashing on a product they spent thousands of dollars on, especially products that they want to believe are perfect. I will try to provide an honest review here about everything I can think of regarding the product from packaging to installation to handling and ride quality.

Packaging:
Excellent packaging in my opinion. The coilovers came in double boxed and bubble wrapped for protection, which really helped protecting the coilovers from the USPS’ bad handling. Package weighed 40lb.





Machining:
These coilovers are machined with stunning precision. I have to say, hands down, the best machining I have ever seen. All the edges are sharp and flow incredibly smooth. I actually spent hours just looking at the machine work and trying to find flaws but could not. AMR Engineering uses Hyperco springs with spring stiffness according to your need. Mine were 650 F/450 R.
Enjoy the eye candy below!







Installation:
The install took about half a day because we ran into a problem. The rear spring top isolator did not sit in the spring mount as there are three tabs to hold the oem isolator and the top isolator is too small. see below:




I talked to Andy at AMR Eng. about the problem but he did not have a solution at that time. Later next day, Andy told me there was supposed to be a cutout template for the top isolator supplied with the package, which I did not receive. We decided to hammer those tabs and install the rear spring. I feel really disappointed that the top isolator did not come precut. I thought this product was specifically designed for the G37x. How can such problem not be accounted for?
Other than that, the installation was a direct fit.

Ride Height:
I chose to lower the car only minimally as I need my car to be drivable at heavy snow conditions. Originally, the ride height from the ground to the top of the fender was 28.75” but now I stand at 27.5” which is 1.25” lower than stock height. This is a mild drop yet the car looked more aggressive. My friends were able to notice the drop. It is more prominent in person than in pictures. This is probably the least drop you can get from the coilovers, the most would be an extra 2.5” drop, which should completely get rid of the wheel gap.

Before:

After:




Handling:
After putting more than 100 miles on the coilovers I have to say, handling improved drastically! I won’t say ten folds, but about two to three times. I can easily corner at higher speeds without my car oversteering, the car feels like it is glued to the road. Body roll has diminished and you cannot feel it at all. My camber values are -1.4 LF, -1.8 RF, -2.4 for both left and right rear. My toe is within spec. I am still debating whether to get a camber kit or not. And if so, which brand would fit the X model.

Ride Quality:
This is the part everyone is waiting for. Obviously the ride quality is what you sacrifice for improved handling. I have the damping set in the middle. I can feel almost every small bump on the road, uneven roads become more notable. Personally I don’t mind the stiffer ride but the noise, oh the noise. With an oem setup, the rear spring makes so much noise it is uncomfortable to drive without loud music. There is a clacking sound, it sounds like something loose in the trunk. This noise occurs on uneven roads, which are pretty much all roads. I went to the suspension shop twice to identify the source which we speculated to be the spring hitting the height adjustment ring so we increased the preload but to no avail. I think the sound is either coming from the spring hitting the height adjustment ring since there is no isolator between them or the tabs hitting the car body. I will try my best to fix this issue.

Update 10/22/13:
Good news and bad news. The good news is I got my SPC front and rear cambers kits installed and everything is spec with current ride height at 26.8" all around. Bad news is that even after cutting out the top isolator and bending the tabs back to the way they were the sound in the rear did not disappear. I am now sure that the metal to metal contact between the spring and the height adjustor is causing the noise. I will try and get some bushings to reduce the noise. once I get them installed, I will update this post.

I hope this helps anyone trying to get these coilovers for their G37X. I will update this thread if anything happens.
Hal