Thank you for your question. First of all there is a technical difference between Manufactured and Modular. Modular is generally allowed any where as they look and feel like a normal stick built home, and in fact can be stronger as they are built to be lifted in place by a crane. A manufactured home on the other hand has a mobile home chassis and is delivered to the site on it's own wheels and chassis. Modular homes are generally allowed everywhere on a normal buildable lot unless restricted by subdivision covenants as a type of construction. A manufactured home may be restricted also by local covenants and restrictions in subdivisions as a general rule. To my knowledge there is no minimum lot size as long as it is an approved buildable lot.
Hope this helps.
Let me know if I can be of additional assistance in any way.