I bought these about 5 months ago and finally got around to installing them.
First off- the install:
The instructions are kind of lackluster, for a DIY job it would have been helpful to have more detailed information. For instance, there are 8 subframe collars, 2 front of front subframe, 2 rear of front subframe, 2 front of rear subframe and 2 rear of rear subframe. However, the instructions only mentioned 3 pairs and the 4th pair (front/front) just had a sticker on them that said "May Not Be Required". Helpful stuff, not. It turned out that the front collars are indeed needed, in fact my car was so far gone that none of the original plastic sleeves remained at all. This is not a job you want to undertake on the ground, find a lift, you'll need a separate jack and 2x4 to carry the rear subframe for the install.
Did I mention that there was slop? Indeed, the bolts were set in the subframe holes with a solid .200" of play around them. All of them. I had a severe thunking noise front and rear for the longest time that the dealership refused to track down (said it was normal for these older cars to make that noise). Particularly when accelerating over a pothole or hitting speed bumps, the noise and associated feeling could have scared the dead to life.
This car drives better than the factory fresh models on the dealer lot. I had thought it was just something Genesis had improved in the new cars that made them handle and ride better than my 2nd gen. The car rides much better on bumpy or challenging road surfaces, with only road noise being present and not body noise. Launch control is greatly improved and eliminated the shimmy feeling I had, as well as some tire spin. I think I will have to get another 4 wheel alignment because there is no way it was aligned correctly before. Hitting the twisties has much more reassuring handling and no shifting feeling on the switchbacks. The ride is also not harsher, if anything it got even smoother in Comfort mode.
This is probably the best $115 I spent on this car, considering it regained so much I didn't know it had lost. I have to imagine all the new G80s will eventually be suffering the same issue too, although there are no collar kits for them yet. There is also a differential bushing kit but I haven't convinced myself I want to spend $500 on bushings and $500 on tools to install them...exhaust mods will be first. Namely an X-pipe.
PS: Maybe Sal could add these to the store? Just a thought, those BH series collars could use some company.