So far the stiffest vehicles I have owned are a 370z and my 2019 cx5. The cx5 feels a tad more rigid. The floppiest were my 1988 mustang gt and 2011 c6 z06. The latter, was quite a shock. I could almost watch the chassis twist when I angled up or down slanted drives, and you could hear the interior shifting. Wild.I thought our van had a nice tight unibody, till we moved to our new house. You can hear it flex as it comes into and out of the driveway But the 300 never did and it doesn’t sound or feel like the truck is
Looked up numbers
Cx5: 31,185 nm/deg
2003 mustang (stiffer than my 88, factory, but I had welded in sfc,so...): 16,000
Chrysler 300: 17,897
Corvette c5: 9,100, corvette C7: 14,500. I presume my c6 z06 was in between.
Porsche 991, 911 Coupe: 30,359
My cx5 feels like its carved from billet. Seems it is indeed comparatively very rigid.