Our "toad" is a 2009 Ford Escape Hybrid (about 3700 lb), which can be towed four down, pop her in neutral, set the key so accessory is not on, and off we go! Roadmaster Falcon All Terrain tow bar, and a US Gear Unified brake system.
Have used this set up with two other rigs as well, and for some reason, in the short 400 or so miles that we've towed the Escape behind the PC, we do "notice" the car. Previous experience with other rigs, it just rolls along nicely, not talking back. But with the PC we experience a little sway and some up and down motion. Hard to describe. On a wavy road (some up and downs) there is up and down re-action from the car. In addition to swaying in some circumstances. Not severe, but noticeable. Our 2010 - 2551 has new Bilstein shocks, and Roadmaster sway bars front and rear. Last thing to double check (can't do it here in our lumpy driveway) is whether we're "level" when on the hitch. It appeared to be by eyeballing, but haven't done a precise measurement.
Hate to think we'd have to also get a rear track bar.