2013 Cadillac XTS. How do you adjust the ride to make it more firmer or softer?

Look in your owners manual or ask your salesman. It's a new car and they should have run through the controls when you bought it.

Good answer. May I suggest he/she sit down and READ the whole manual. How can you spend $60- 70k and not bother to read it. Someone needs to get their head out if the place the Sun never shines!

From the owners manual, page 9-31. Tour: Use for normal city and highway driving. This setting provides a smooth, soft ride. Sport: Use where road conditions or personal preference demand more control. This setting provides more “feel,” or response to road conditions. The vehicle is normally in Tour Mode. Sport Mode is engaged when the shift lever is placed in M (Manual). When the shift lever is placed in D (Drive) the system will revert back to Tour Mode.

If you want the ultimate soft ride,invest in air bags on all 4 wheels!! It'll run you between $300-$800 ( depends on many factors)per wheel but well worth it! Like the ride of the "big boat" caddy's, like a marshmallow!! They do come with air ride on the rear wheels but much smaller and tuned for cornering- not comfort! Why did they bother?!?! Other than air shocks, the smallest wheels you can get(18"-19") with 1" taller tires than standard will help a lot also.