Welcome to the forum.
I can't help with your specific question, but it's very likely someone on this forum will have some information.
In your post you said, 'I test drove it and it was very affected when trailer trucks passed and seemed to sway a lot.' One thing to check is the tire pressures; they might be low.
Inflation near the upper end of the tire's pressure range will help stiffen the sidewall and reduce sway. Higher pressures can make a harsher ride and the dealer usually wants customers to feel a softer ride.
Sherm & Terry w/rescues Steve (std Poodle) & Eydie (min Schnauzer)
2015 Jay Flight 27RLS (Camped: 102 nights 2015, 90 nights 2016)
2006 Ford F350 6.0 PSD, Lariat, 4WD, CC, LB, SRW, auto., Camper pkg.