RE: Trailer rash?
I have a home built trailer made from a 12 foot flat deck many years ago. It will hold two 40% planes (three pattern planes with the stabs off) and I have never had any problems transporting over long distances ( it's in my photo gallery). My trailer is small 12x6x4 and light. However, a regular size cargo hauler ( similar to a haulmark) with springs is a different story and a rough ride for sure and I have had damage done to my IMAC planes back in the day, while traveling rough roads. You will find that things you install in the trailer tend to come loose.
The torsion suspension is the best by far (like Gary C indicated), smoother ride, tracks better behind the vehicle and not hard on airframes, etc.
Hope that helps.
bholsten