As stated I was thinking about changing my race with G points and I was wondering if/when I do that will I loose all the Special/unique mods that I have installed right now I am a Sillixx Fixer. I was thinking of becoming a Genetarr Fixer.

If you go over on decks slightly random tier rewards (space 0) become ineffective but if you go way over random modules become ineffective.

They are still there, and when you fix your deck shortage they return to normal.

I recommend stockpiling Ship-bots and Rank Points (if necessary) until you have enough to cover the decks you will lose when you switch off Sillixx.