Confidential information and agreeing not to use it for competitive purposes: Matters concerning the due diligence investigation are to be treated in confidence and the purchaser will not either directly or through his representatives divulge any such information. The purchaser is also bound not to use the information gained through due diligence investigations in competition with the seller even if the proposed sale falls through.
The difference is a Letter of Intent is basically a letter stating the kind of offer you are contemplating in making. Usually it contains what I call the GENERAL items of price, terms and closing date. Most of the other legal STUFF is left out.