Firstly, it's a 2011 G37S 6MT and I decided to buy used coilovers for cheap$$$$ which is the worst idea ever. Never be like me. So I got used "JDM" HKS Hipermax III's for the Nissan V36 Skyline and I put them on the car. Well it turns out after a week of driving the Left Front strut mount rubber was disintegrating, just trash rubber in the mount. So for most of the year I've heard rattle rattle bang bang on bumps - any bumps - riding on a busted top mount with the strut wiggling around in the mount . The Car drove and handled SWEEEET though! Can't say enough good things about the handling of the HKS Hipermax's. I spent 6 months trying to acquire a new strut top mount through HKS Japan, referring me to a dealer so I chose Z1. Z1 goes through it's procurement process and takes my $125 only to tell me the part is NLA several months later and refund my money.

For the record I knew the part was NLA on the Hipermax III's. I was hoping someone might sell me a Hipermax IV top mount and tell me the parts were the same, but alas that never happened. Anyone got a set of HKS coilover front top mounts? It's special, not like the original OEM strut mount. HKS doesn't re-use the top strut mount. I'll buy a top mount to save my HKS coilovers.

Fast forward to a few weeks ago and I score a set of KW V1's in very nice condition, used once again. I install the fronts, reusing the OEM upper strut mount and it fixes my rattle bang bang driving down the road. I love the KW's ride, but preferred the HKS adjustment capability, The HKS just do not work with a standard OEM front strut mount, so I've been rolling on the KW's for weeks and loving that.

Last night I decided to tackle the rears on the KW's. One of the last things I did was put my impact on the 12MM top nuts holding the rear struts in place and I snapped that stud right in half. **** ME.
On a sedan. Pretty simple fix in a _coupe_
I decided to leave that broken strut bolt in place and see how the care drove. IT DID NOT DRIVE WELL. It did not drive well at all. That particular wheel felt like it was twisting under load and rattled like crazy.

So I got to take it all back apart last night, pull the back seats, get my sawzall and and an angle grinder and cut myself a new access window to replace the right rear strut stud I snapped tf out of. I got to drill out the snapped stud and I had the pleasure of half-assed tapping a new M8 bolt and tack welding it in there. I finished it all off with a little rattle can black magic. GOOD TIMES YA'LL

Car is in the shop getting new rubber and a fresh alignment today. FWIW I preferred the HKS rear strut and helper spring ride over the KW, but I've only had about an hour today to test. Currently IMHO the KW's feel more bouncy and the rear seems light. The HKS setup in the rear felt planted, stiff - not bouncy.

I didn't take a single picture of any of this ****. Coilovers can kiss my grits

 

I didn't have the same experience as you but I had some drama with my Fortune Autos. Admittedly, I used the BC coil-over walk thorough for my install and the car just never rode right. It was really stiff on the softest settings and the rear height was always just a little off; just felt very tight and would knock a filling loose if you hit a slight deviation in the road. Got to the point where I pulled the Fortune autos off and reinstalled the stock set-up. Drove with that for about three months and was quickly reminded how much I hated the stock ride height.

Anyways, I listed the Fortune autos in the FS section and started boxing them up and getting the paperwork ready and what not; for whatever reason, started flipping through the directions and realized the install instructions and min/max height for the shock unit into the assembly was different than the BC coilovers (go figure). I gave the install another go and followed the instructions and tips to the letter. The issues I had before were gone and the car has a firm but very smooth ride; with a ton of stability going around corners. Also bumped the rear up almost .5 inch and fixed the slight sag it had.

You're not alone..We should probably put together a support group for the forum.