python - is it ok to use files inside pip packages without installing them -

i working on project , have cloned repository github.
after first compile realized project cloned has dependencies , in requirements.txt file.

i know have install these packages, dont want cause on windows development environment , after finishing project going publish ubuntu production environment , dont want take hassle of double installation.

i have 2 options:

1. using virtualenv , installing packages inside it

2. downloading packages , use them direct way using import foldername

i wanna avoid first option cause have less control on project , problem gets bigger , bigger if example inside project's virtualenv , wanted run project's main.py file own virtualenv , etc... moving virtualenv windows (bat files) linux (bash / sh files) seems ugly me , directs me approaches choose better avoid.

the second option choice. example need use future package. scenario downloading package using pip download future , when done extracting tar.gz file, inside src folder can see future package folder, , use import future_package.src.future without touching else.

aside os.path problems (which assume take care of):

is practice?

i not running setup.py preventing installation. can cause problems?

is there better approach involves less work (like second one) or better 1 mentioned first approach?

update 1: have extracted future , certifi packages part of requirements of project , used them direct way , working in particular case.