Bought my 2015 Tahoe LTZ 6 months ago.now 11,000 miles later still rides like a wagon.changed 20" continental tires to 18" Michelin, put 32 psi in both sets of tires with very little change in stiff ride and still has vibration at any speed. My Dealership installed a whole new rear end at about 6,000 miles, but did little to change the stiff, vibration. The rear Magnetic Ride Shocks are 1" from the top of the useable shock travel which to me leaves very little play left for the ride to absorb road conditions.I still own a 2004 and 1998 tahoe plus other GM products within my company and have been a GM customer since my first chevy ll in 1966. I have never been disappointed in all the cars and trucks I've bought over the years,It's always exciting to get a new vehicle but this 2015 Tahoe is not only disappointing but after 11,000 miles it makes me mad every time I drive it, you would think GM would expect a $65,000 car to have a reasonable, non vibrating, comfortable ride and not the stiff , vibrating ride we are getting. I must add my Dealership has been very understanding and I believe has done everything that GM has allowed them to do BUT still has NOT even begin to solve this MRS problem. The GM rep also came an somewhat agreed It was not what it should be but stated that was the characteristics of Magnetic Ride Suspension and didn't know of any way to fix as of now. It was also the only 2015 Tahoe he had driven. So, Please Mr GM, fix my car so I can continue to buy GM products.