Okay - now I found out how to really get 5 stars. It doesn't depend on $-tokens. Just collect any token you want. Each 5 tokens collected means an additional star (as long as you don't lose a life I think):
5 tokens collected: 3 stars
10 tokens collected: 4 stars
15 tokens collected: 5 stars
So it's possible to have 5 stars after the 5th goose copter. But you have to destroy each of them before they are assembled or you won't get enough tokens...
When you have 4 stars and die you'll have a SLOW 4-way shot afterwards.
When you have 5 stars and die you'll have a FAST 5-way shot again which is indefinitely better than the slow 4-way-shot.
I always just restart the game when I lose my first life before obtaining 5 stars (which still happens most of the time).
You can have 5 stars and thus be "upgrade-independent" as soon as here (very first water area):
@Shoonay: Ah, didn't know about RefreshLock - good to know. (Still Powerstrip works on my Vista 32 and lets you create custom resolutions.)