The following has nothing to do with LEN: Ask the builder if they have a 'Standards of Construction' document. Some builders may now call this document, Performance Quality Standards. Some builders may call this document by another name, but its contents will be the same. Obtain this and read it. Pay particular attention to the term, 'standards of the industry'. This will give you an indication of the quality of your new house deemed acceptable by the corporate/public new house builder. Do not assume your house will be of the same quality as the builder's models.
Ask YOUR ATTORNEY to modify/delete the arbitration clause. If the builder is not willing to do this go elsewhere, or require that monies be escrowed to protect your interests. NOTHING in the documents you sign is designed to protect YOUR interests aside from the transfer of title. Fannie Mae and Freddie Mac will no longer purchase mortgages when the sale contract contains an arbitration clause. This should speak volumes about the risks involved in the purchase of a new house.
Ensure that your attorney, if you have representation regarding ANY aspect of your new house, is not a shill for the builder. Ask the attorney if he has represented, or is currently representing, other customers of the builder, has ever filed a lawsuit against the builder, has ever participated in an arbitration against the builder, has ever refused an arbitration with the builder, and what were the circumstances and results of any of these proceedings. Do not assume the attorney or the builder will behave in an honorable manner.
An independent, pre-closing house inspection will not protect your interests regarding leaking windows, a leaky roof, a faulty foundation, settling/heaving/shifting concrete flatwork, or other long term consequences of shoddy construction and other cost cutting measures.
Do not assume you are dealing with honorable people. Get an independent, second opinion regarding ANYTHING of substance related to your new house. YOUR interests are YOUR interests, only.