Originally Posted by Jhill

Yea the bmw towers and subframes were too thin so thats not exactly a fair comparison because they crack even with stock form. Maybe I wasn’t clear in my description of his explanation but he was pointing out that in stock setup the largest hits (bottom out) still send the force to the shock towers not the sub frame. Some vehicles (mostly trucks) that use separated spring/shock setups still have the bottom out bumper on the frame. Converting this type of suspension to a true type coil over would be more concerning because the towers were never intended to handle a harsh impact. That isn’t the case in the z because the shocks still have the bottom out bumper therefore the largest impacts are still getting sent to the towers. So like I said the route I went didn’t offer two versions and I hardly ever change ride height plus if I went true type I’d want to replace the bushing in the knuckle where the shock mounts with a spherical bearing since that bushing would see more force and I wanted to stay relatively oem for NVH. But this explanation would be more comforting to this deciding to go true type.