Welcome to the Forum! If you know which trim level and RWD or AWD, let us know and also update your profile with that info. I know Koni was going to make some FSD's for the ATS, but I think those got scrapped just before or as they became available. It might be worth looking into some Bilstein B6 or B8 shock dampers, or into coilovers if you want to spend more for more adjustability. If you use the Advanced Search function, you will be able to limit the search just the ATS forums for certain words or phrases which will be really helpful to find what others have done. Good Luck!

 

As a student of suspension and steering technology, I would advise buying only OEM replacement shocks and struts. They are engineered into the vehicle's handling characteristics and software programming. Don't try to out think GM on this one.

 

I second the OEM struts only. For all vehicles but especially a higher end one like a Cadillac.

 

Add me to the OEM only list. GM has some of the best suspension engineers in the business and the systems are very well matched to the vehicle, especially for those platforms that are biased towards performance like that underpinning the ATS.

Unless you want to greatly change the handling from stock (which also means a lot more than just changing the damping part of the equation to do it right), then stay with OEM.

At a minimum, replace both pieces at that end of the car because there will be a difference between new and a well used older piece and that is particularly true with the passive struts used with non-MSRC vehicles (basically those that have premium trim and are not equipped with AWD). About the only time you can reasonably replace only one of the two at the end of the vehicle is with a nearly new vehicle where one piece suffered severe damage.

Rodger