The sport model has the following options.

• Chassis Damping Control
• Performance suspension

If you order a premium luxury model with the platinum package you get the upgraded suspension.
I am assuming your loaner was not a PL Platinum thus the difference in ride quality.

 

Bigger wheels might have something to so with it. Less sidewall to flex. My 20 AWD Sport with 20s rides fantastic. Definitely passes the wife test. Rides better than a 19 Traverse High Country we had.

 

The 21s come with contis 20s with michelins

 

Not sure tires on the Sport, but the Michelin Primacy Tours on the Premium Luxury are trash.

Can’t recall last time I’ve experienced such a LOUD and hard tire.

Test drove a Luxury model with standard equipment and impressed with how smooth and quiet it was…typical Cadillac.

My Premium Luxury has the upgraded suspensions and like you said can feel, and especially HEAR every pit, pebble, ripple, expansion joint, etc. in the road. Very unbecoming of a supposed luxury vehicle.

Unfortunately tires passed inspection so Michelin wouldn’t do anything. If I want to replace, on my own dime.

 

Upgraded from XT6 Premium Luxury to Sport . 21 Continentals . Ride quality improved on Sport . While the PL rode decent . The Sport has improved road manners. Braking vastly improved with the big Brembo front red calipers. ( looks nice too ) . Sport has better shocks ( magnetic electonic ) where a computer is constantly monitoring road conditions .Steering may be more responsive too . Think Cadillac calls it real time road sensing suspension . Sport is worth the increased $$$ .

 

Yup, have a 2021 XT6 Sport. GM calls it real time damping suspension. Have taken it on drives from Alberta to Arizona and twice to Las Vegas. Have the 20 inch Onyx Black package and it rides beautifully. Also has the intellibeam headlight which made me upgrade my headlights on my 2016 Camaro SS.