Q: After 89k miles, my 1991 Carrera is feeling a bit arthritic and loose over bumps. I am considering Bilstein coilover struts. I also want to lower it about an inch and a half but I am afraid that the ride might be rough. What do you think? – Fred
A: I like that combo. Even without adjustable damping, the Bilsteins work great. They are biased more toward crispness than comfort but on a Porsche…Perfect.
On the other hand, if you simply install the kit without considering other components, you might be disappointed and blame it on the shocks. Often, poor ride characteristics are caused by the rear upper strut mounts, front control arm bushings, and stabilizer bushings.
You can’t see the rear upper mounts when they are on the car. But when you do a side by side comparison of old mounts to new, you will see the difference. Since most of the cars weight rests on just two rubber donuts, after 17 years, the mounts are well done. Over time, rubber hardens and settles into a fully compressed shape. The front mounts on these cars seem more durable and they are expensive. I have not seen the need to recommend them even on higher mileage cars. Rubber deterioration also affects the front control arm bushings and stabilizer bushings. The bushings get twisted every time you hit a bump or bend your toy around a corner. And you thought you just needed shocks.
My rule of thumb for rubber suspension parts is: With a useful life of 10 to 20 years, when the struts and shocks are being replaced, replace the mounts and take advantage of the labor overlap. – MC