It's probably not a big deal in this case (since this function shouldn't be called very often), but we could cast it to an FlxSprite in order to prevent Dynamic operations:
```
public function add(Object:T):T
{
var sprite:FlxSprite = cast Object;
sprite.x += x;
sprite.y += y;
sprite.alpha *= alpha;
sprite.scrollFactor.copyFrom(scrollFactor);
return group.add(Object);
```