I just had my starter replaced and at first the car started up REALLY quickly. I'd grind the starter trying to get it started everytime.

Now, the starter makes a squealing noise when I try to start it, but it does seem to start up pretty quickly. Is this something i should worry about? Or it just the starter breaking in?

 

There is no such thing as breaking in a starter.

Are you sure its not a belt slipping (now that the engine is turning over faster)?

 

That doesn't sound right...

When you try to start and already started car i'd expect a squel.. but not from a non started state.

 

Went to run a few errands today and it wouldn't start in the parking lot of Shaws. I opened the hood, pushed the starter cable (I think it was the starter cable) and it started right up.

When I got home and I parked it, I tried to start it again and it was REALLY REALLY hard to start, but when it finally starts, it starts so quickly that the starts grinds....

 

Sounds like you got a flaky starter that isn't disengaging from the flywheel properly... go back to the shop that put in the starter for you and have them put in another one...