The Downtown Lots come with the .dlt file which must be placed in your UserData/Imports/

*Click the four titles to view downloads for each level.
* Click Lot image to download the Lot
* Interiors are optional.
*We chose to do it this way because the downloads would be larger and take more time and no need to download stuff you have already.

If you do not have Livin' Large or House Party and the house indicates it carries those items, then you may still get the house, but will be missing some things.