The text "New Products for" is defined in languages/english.php

"Model:" can be changed on a product-by-product and listing type basis, so you will find it defined in the following files in the languages/english/ folder:
  • document_general_info.php
  • document_product_info.php
  • featured_products.php
  • product_free_shipping_info.php
  • product_info.php
  • product_music_info.php
  • products_all.php
  • products_new.php

These are easy to find using the Zen Cart Developers Tool Kit