Installing extension in HD first then move whole portable ff to flash drive

Hi, I got a new flash drive and I want to install portable ff and this is what I thought to do

1. Download the zip from this site
2. Unzip it somewhere in HDD (C:)
3. Install extensions because HDD access is faster than Flash drive
4. Move the whole DIR to the flash drive

Can I do that? would it corrupt something?

Thanks