Second to last trade up we went from a light 17' TT to a 30' rear kitchen with a 1/2 ton of hitch weight. The dealer swapped out our old 500# spring bars for 1200# bars ZERO cost and the 1200# bars were brand new. All I had to do was ask. By the way we went back and got our latest TT from the same dealer. Quality shops deserve repeat business. I wouldn't go to that dealer again that wanted $1200 for $500 job................camp safe
P.S. tow vehicle is a GM 2003 2500HD 4X4 gasser I've had since brand new. If I was to buy again I would go with diesel.