Better to trim plastic molding than adjusting the suspension it trimming will take care of the problem. By adjusting suspension, shop probably means lowering the truck which may make the truck ride harder.
As for getting it done I would recommend contacting one of our local installers by going to the following link:
http://www.tirerack.com/installer/index.jsp
If they cannot directly help you on this they may be able to recommend a local shop.