[SeanPagne]

Why haven't Chrysler updated to aluminum suspension parts other than to keep the cost down? And why haven't I been able to find any aftermarket Al parts either?

Even though the suspension is copied from Mercedes, it still doesn't ride as well as one. The spring rates, bushings etc. on non SRT models are fairly soft, and the chassis is very rigid. I've probably overlooked a couple things, but the only major difference I've found is that Mercedes use Al arms compared to our steel arms.

I've recently gotten myself a Saabaru 92x, found out it came with a pair of aluminum arms in the rear for better ride, and was very tempted to swap the steel front LCAs to aluminums from an STi. Just thought this might actually be a more useful upgrade for luxury sedans than my mutant WRX. :biggrin:

 

[Gibby]

Look into chromoly control arms. Aluminum isn't necessarily the best choice. It's used in manufactured vehicles because it's easy to form from a template (casting) and lighter than steel. But tubular chromoly parts are stronger and lighter than cast aluminum parts. Any high-end aftermarket suspension component will be out of tubular chromoly. Everything from control arms to panhard bars to torque arms.

 

[NavySRT]

Early models had aluminum upper control arms in the rear, but Chrysler switched to stamped steel at some point along the way, at least that's what I gathered from reading the instructions for my CST bushings. I had the aluminum versions.