[radz28]

09/11/2023 - UPDATE:

I'm probably the only dingus that this has mattered to, but I'll update anyways.

My OCD has been driving me crazy since starting this enterprise. Because of not doing research before my purchase, I did not understand that I'd be losing some measure of spring rate when moving to rod ends. I'm still not that positive on precisely how much spring rate I've lost, but, I did take a control arm, place it in a vice, and used a scale to see about how much pressure the rubber bushing applied at about 1-inch and about 4-inches of travel. The force I measured was about 7-lbs @ 1" and about 30-lbs @ 4". I was trying to get a spectrum from a little above ride height, to about full compression (I'll freely admit I hadn't tried to actually measure full compression, so I took a guess). I replaced 3-arms (per side), and each arm had a rubber bushing that was replaced by a rod end. So - even though I think I found a spring rate calculator for this, I didn't really take the time to calculate anything. BUT - I figured it couldn't be zero, so it was just driving me crazy.

In another moment of dingus, I thought if I slapped a bigger stab. bar on, it would make up for the difference, but that would only help in corners... Then - my OCD started going crazy because the front suspension balance might be off, so I, then, upgraded the front (aFe adjustables). I was still stuck with not compensating when going straight, and couldn't decide on risking more money and time on likely a fruitless effort, and, likely, possibly, losing some better weight transfer on the strip with softer spring rates in the rear (as a result of the rod ends). My OCD just couldn't accept throwing the OEM balance out of the window.

SO - I settled on a set of BMR springs, ONLY for the rear. The rate wasn't crazy-higher than OEM ZL1 coils, and even if it was, there were still 3-more rubber knuckle bushings I know I'll replace later, to compensate for (the lower control arm pivot looks like a spherical end), so I was future-proofing for my OCD. I was a little worried about ride height (as these are lowering springs), but more-so, losing ride quality. As it turns out, I am pleasantly surprised and happy with both. Before the coil install, my ride height was about 27.5-27.75", front and rear. It seems a little lower than stock from other information out there, but with the added weight of the 2650, and less spring rate from the rod-end-control-arms, it seemed logical. I've only put about 50-miles on the car, but it seems I haven't lost ANY height (it actually measures slightly higher than before). They might settle (or the rubber insulators) after a little more driving, but if I can keep it close to where it was, I'll be even more happy. The ride seems VERY comparable to OEM springs, too. It definitely wasn't too stiff at all. Driving over the same roads I have didn't yield much of any difference in ride quality and everything is about as good as I could have hoped for.

So - for anyone trying to make up for spring rate loss as a result of control arm rod-ends, these BMR (lowering) springs, with higher rates them OEM, seem to be okay. I recognize they may not be as optimal as YYZ and what not, but I didn't need and want a whole set, nor did I want to lower the car. So far - these seem to fit the bill great, and when I get around to replacing the last of the rubber bushings in the knuckles, I'll have some spring rate "in reserve". I wouldn't say I recommend this, but for my purposes: I am very happy and my OCD, for this aspect, is at rest.

09.02.2022 - UPDATE

Everything seems to continue to be as good as I have expected. This isn't a thorough review for strip/track experience, but it's probably about as far as possible for the street. I've put probably at least 500-miles on the arms now.

This will probably be a 1.5-part review, as I haven't put my Mickey's back on yet, but have about 200-street miles on the these parts. Chassis/tire-wise, my car's still stock. I have about 2400-miles on it, so it's still "new". I don't have specific plans for the car, though, I'll be hitting the strip by my house more than a course, even though I'd like to do that a bit. I didn't want to sacrifice much drivability or NVH though, which was almost tied for my biggest concern. My biggest being the rear sway on DRs, because the way the car moves around above 80-MPH was downright scary to me. THIS needed to be fixed. My .5-part of this review will be a small follow-up once I get the DRs back on a Hoon' a bit to see if anything's improved.

I purchased ZLE Cradle Bushings, and BMR Cradle Brace/Upper and Lower Trailing Arms/Upper Control Arm/Tie rods (all in rod ends). Unfortunately - I replaced everything at the same time, so I don't know how effective anything was on it's own. Everything else in the chassis is stock, and I had a wheel alignment performed right after the install.

As expected - there's a little more noise from the rear. I don't feel like I'm getting drivetrain noise or whine or anything from the diff'. I can hear a little more rattling or chunking going over smaller cracks in the road, but nothing much from expansion joints or anything. I might get a small pop when the suspension flexes over going over speed bumps diagonally or when crossing gutters the same, but that's about it. I think I would say I can "feel" the rear more than hear it, if that makes any sense. The car seems to go straight as before (well - before swapping t the DRs), but I'll have to circle back to this assessment when they're back on. I think I'll be able to deal with the additional NVH though, if it doesn't get much more pronounced, and as long as it goes straight with the DRs.

It's my understanding that going to rod ends lower spring rate a little. I can't evaluate that, but it makes sense. I don't know that even if I were a driver good enough to notice, that I'd get the opportunity or even be serious enough to feel the difference, so I don't think that's a big deal. There are custom springs and such to make-up for that if the need arises anyways.
There might be comments about SPL-parts, but I didn't need to invest more than I did with these parts, and I've had good experience in the past with BMR stuff, as true as those comments might ring.

I'm pretty happy so far. I'll follow-up soon with DR impressions, so fingers crossed!