
First take note of the two circles i made in Vegeta and Goku's aura's, labeled 1 and 2.
Clear difference is that Vegeta's has a distinct "star shaped" stuffs floating. Compare that to goku's small bubble shaped one.
Now look at the aura shades, 3 and 4. Vegeta has almost 3 tones of color. Pale blue, the Cyan SSB and a Navy Blue. The last one isnt present in Goku's.
Here's another picture for comparing Goku's aura
[spoiler]
[/spoiler]Also note that they actively avoid showing Vegeta's Pupils. Also, Vegeta's hair color change is pretty apparent
Now to throw in my theory:
A counter point to this is Vegeta's line before his FF: "Kakarot can have his Ultra Instinct, I will defeated you win with my way"Has it been said that to get UI, your hair needs to be black and you need that white aura?
I believe that Vegeta will be able to mix UI and Blue to some extent.
UI's power increase for Goku is related to him getting his full potential out.
While Vegeta can get UI and still stay Blue.
Makes sense now.




