My dumbass didn't take rear pictures, I'll update this later. Apologies for all the edits Cliff, I haven't ever imbedded this many images on your site before...

For context my car is an 86 SE, 3800SC 4spd, poly control arm bushings, stock front brakes, grand am rear brakes. 17" wheels running Falken RT660 tires for racing.
Before coils I had stock Y99 RPO Springs that I cut a single coil off of on each corner, and some bog standard FieroStore KYB shocks.

I have installed and now gone and participated in a national autocross event, both with and without the coilovers so comparing is based off experience.

To start:

Installation was a nightmare. The rear coils went in fine, but the fronts were tragic. I was either sent the wrong mounting hardware or they legitimately didn't test the fit, but I had to cut and reweld the lower mount so that it wouldn't interfere with the brake caliper. Stock brakes, stock lines. Without completely redesigning the front mount, the brake caliper hits at 1 full turn of the steering wheel. This is a common complaint seen mostly on Facebook from the 3 people who have ordered and installed these. Most of the people who have complained said that it was a problem with upgraded brakes, but I can confirm, it's a problem with stockies too.

Pic 1+2 are how it's supposed to go on, and how the mount looks on its own. Pic 3 is after I cut it and tried to see if it would clear. Pic 4 is after cutting enough clearance to mount it backwards in the control arm. Pic 5 was the reweld to reinforce the now weakened mount, and it hasn't broken yet so I guess I did a good job. Pic 6 is it mocked up pre weld.






Past the mounting, cutting out the bumpstop for the spring sucked. Maybe I did it wrong, but it was an awful endeavour. You have to cut out the ENTIRE thing so that the adjustable spring perch actually has a place to sit. The bumpstop does not unbolt, cutting or melting it is your only option AFAIK. Ride height adjustment for the front is done via that adjustable perch.

It's worth mentioning that after getting in touch with Hiro, they sent me a new lower mount that looks closer to the stock shock mounting.
I haven't installed them as I did so much work to get the original ones to fit that I'm stuck in the sunk cost fallacy.

They ride pretty rough, the spring rates are harsh, but that does equal some very good cornering performance. The ride quality for daily driving is unbearable, I'm 22 years old, my back can take a lot still but it's simply too harsh to be enjoyable. I have the benefit of this being a dedicated race car, so that isn't so much a problem for me.

In comparison to the cut springs and poly bushings I had before, the performance difference is incredible. Body roll is now 1/4 of what it was with the cut springs, the car is super darty, and it feels so much less floaty than it did. Steering effort was slightly decreased it felt like but that's hard to judge on a scientific level as the caster didnt change. Understeer is still a slight issue, but I believe that's driver error more than the car. You can really throw this thing into turns and it'll take it as long as the tires your on can handle it too. Im sure adding a rear sway bar would make this car perfect feeling. They're 32 way adjustable, and there's noticable change from 1 to 32. 1 being softer, and 32 shaking your fillings out on the slightest surface change in the road. They have preload adjustment which I haven't touched, and plenty of ride height movement. I have the car about 6.5 inches off the ground as to save the impossible to find gas tank from having a drain hole installed by accident, but it could go much lower. Rear camber is easily adjusted the same way the stock struts were, the bottom bolt on the knuckle is ovaled out for a lot of adjustment.

Overall, the performance is good, but the end result frankly does not justify the work required. (Unless they start shipping these with that second mount I was given.) Especially not for 1000 dollars. You would probably be better off attempting to source Koni shocks and some Eibach or WCF lowering springs. Your mileage may vary, but this was my experience. If I missed anything or you have any questions, I'll happily try to answer them.

[This message has been edited by Additivewalnut (edited 05-22-2024).]