I flashed rubix 2.0 and i want to use one of his themes as well. i have the file do i just flash ontop of the rubix rom? do i need to wipe anything first?
Nope, if the theme is for your current rom version per the theme post you simply
1. Make sure theme zip is on your SD card and boot into clockwork using bootstrap app.
2. Mount system
3. Install zip from SD card and find the theme zip
4. Reboot. Initial reboot with a new theme usually takes a little longer so be patient.