I would bite the bullet and get the approved trailer. My reasoning is you don't want to turn down a potential client because your rig is not HD approved. This may lead them to question your business as a whole. Even in ares it is not required, having HD approved equipment will set the customers mind at ease a little more I think. When I go rattling off the list of lawn equipment companies I am a "Factory Authorized Service Center" for it impresses the customer. doesn't mean I am a better mechanic because of it, but in their mind it makes me more professional and qualified.
Dedicated Stick Burner, Pitmaster @ All About The Q, facebook.com/itsallabouttheq KCBS CBJ