It's probably a moot point at this time, however putting the smart car in the back and offsetting weight to the front to correct for a light pin can amplify the stress in the frame.

My biggest concern with toy haulers is the lack of loading information provided by MFG. Just because the cargo capacity of the unit may be 3,000 lbs, putting 2,000 lbs in the garage and then 300 lbs or so as close to the front does not mean the frame will not be highly stressed.

It would be nice to see a "loading suggestion" for frames. Essentially it would give ranges of load placed in various parts of the unit to help keep the frame happy. Too much load on each end is like putting 3 full size adults on each end of a 8" wide wooden see saw on the playground. Something has to give (board flexes a lot).