The Maneuver-Assist configuration for the TIE/rb Heavy has the following wording:

Reduce the difficulty of your speed 3 straight (Maneuver: Straight (white)) and bank (Maneuver: Bank left (white) or Maneuver: Bank right (white)) maneuvers.

I'm trying to work out whether that's speed 3 (straight and bank) become blue, or (speed 3 straight) and (bank) become blue.

Anyone know the answer? I don't mind people sharing opinions, but something official would be nice

General Consensus is that the card only modifies the 3-speed maneuvers.

This question pops up repeatedly, due to the fact that English is an imprecise language. When a sentence reads "verb an adjective noun or noun," it's unclear whether the adjective (in this case, Speed 3) refers to both nouns (straight and bank maneuvers), or only the first. Typically, in casually spoken English, an adjective at the beginning of a list modifies the whole list, while adjectives in the middle of the list modify only the specific entries.

it's only for speed 3 maneuver, and just the straight and bank speed 3 maneuvers.

Thanks - that's where we landed.