Basement Entry Door - via new construction or existing foundation

Assuming nothing unusual: does anyone have an idea which is more cost effective: adding a door through an existing foundation (going through concrete sidewalk, dirt and foundation using current window of a 1939 two story brick colonial) or adding a door with new construction (foundation wall only to be 4-5 high). Let me know. Thanks.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
Add image file
Upload is a website for homeowners and building and maintenance pros. It is not affiliated with any of the manufacturers or service providers discussed here. All logos and trade names are the property of their respective owners.