The causes are straightforward
1. Mass -- It is a large vehicle
2. RWHP -- it starts out strong and gets stronger with just an adjustment to the torque management / traction control ECM
3. BHP -- Stickier tires, higher friction pads, big brake kits and the OE Brembo brakes -- Those are Bad A$$ brakes
Take a good look at the radius rod bush. It is a steel-jacketed hockey puck size piece of rubber with shape / voids. It is compliant. It was designed to allow the suspension to articulate, control the vehicle and meet Noise, Vibration and Harmonic (NVH)standards. It was also designed to meet a price point with the market place. If you closely examine a gently driven bush you will find 'smile' lines have formed during use. These lines are nothing more than the area where the rubber surface has reacted with air, dried a bit and then in this innocuously dried superficial layer the rubber has 'cracked'. This is absolutely normal and what would be expected. This is not a problem. When you look more closely at these pictures yo will see how it has progressed.
So what causes this progression -- increased load. Matt ran his car at the track early last week. He has been modding his car for some time. With all of his mods plus Pedders Track II bush kit he was having braking issues. His fluid was boiling and his rotors were glowing. He never had that issue before, but with more speed from the other mods his brakes got comparatively weaker. He increased the load. The brakes began to fail.
I have seen one box stock SRT 8 with torn bushes, but the driver is an animal. The SRT 8 is an excellent car out of the box. There is no doubt in my mind that were I a Chrysler Dealer or Corporate employee I would have denied that as a warranty claim. His tires showed track mark into the lettering on the sidewall -- just like some of mine. I know how hard he has tracked that car. The loads were very very high. That said so is a BMW. BMWs have bush issues for the same reasons the LXs do. Pedders bits would almost never fit into an OEM budget for a production car. I have Dealers with varied interests and services. Pedders has a bush kit for the Superformance Cobra based on a Dealer request. We had existing bits that we felt met the engineering needs for sway bar D bushes and endlink bushes. Other requests for urethane Ferrari bushes don't make the Pedders R & D que -- the market is jut too small. Could Chrysler make a Pedders style voided urethane bush -- sure if they had the commitment from sales to preach the benefits and the will to put an MSRP on the car at over $50,000.
If you search through the LX forums you will also find failures in the rubber strut and shock mounts. Some are from high mileage while others appear to be induced by coilover increased loads. Regardless they are failing. We think that there is a noise element in these mounts. We are looking at a redesign of this OE LX bit. It will probably be a rubber bit as urethane does not bond to our standard for the torsional loads required in this bit. We are collecting failed LX OE rubber strut and shock mounts. We don't see this as a defective OE bit. We see this as an opportunity to serve a market need. Most LX owners will not need an upgraded new and improved strut or shock mount. Because the LX market is so big there is a business case to develop the bit for the most demanding LX owners. As we continue to collect these bits from embers of various LX forums we may find that there is no better solution than the current bit available from Chrysler. If that is the case we will not make them.
Once again, we designed this kit to improve the stability of the platform. It was our opinion that the bushes could be made using our voided urethane design to maintain the civility of the vehicle yet provide a dramatic increase in the handling. In our R & D phase we did not see these bush failures. We designed this kit for the enthusiast driver and for the discerning daily driver. The bush failures were news to us too. We expected OEM bush mush -- lots of compliance and noise isolation. The bush tears got our attention.