On the ultimate edition?

What "stuff" are you referring to, specifically?

There has been 2 free goodie bags released, containing desktop wallpapers, posters, screenshots and concept arts. No ingame items or vehicles.

If you are referring to the "exclusives", like the Wolf School jacket, Black Unicorn (sword) etc. - the rest is on the list here:
https://www.cyberpunk.net/en/myrewards

...then you can easily use the CET console (CyberEngineTweaks), and enter the codes for any ingame item that you want (will be added to your inventory).

Did some search and it seems that the phantom liberty had preorder bonuses, like a car. Quadra something. I was wondering if this and whatever else was preorder bonuses comes with the complete edition.

That particular vehicle, the "Vigilante" if I remember correctly, can be purchased through the Autofixer terminal. $86000.

It's exactly the same as the "preorder" version, except you would have had access to it from the start of the game (a feature that didn't even work for those who preordered the game back at release).

Can't speak for the preorder feature with the Ultimate edition, but yes, you will get the car as you progress through the game.

CET, as mentioned above, supports codes for all the cars too btw. If you get a working version of CET, I can post the Vigilante code if you want.