There is ZERO reason to upgrade the bearings in a new Curado. Flush them with Acetone, and add a drop of Bantam Oil that came with the reel. Otherwize, it's waste of money. You don't get any valuable return your investment.
If you want to do something worthwhile to your reel, get a Carbontex drag from Smooth Drags for about $10. That's an improvement that is worth it's weight in gold.
solid advice, this would be what I would do to my customers reels, unless the bearings have been contaminated with salt water or are bad for some other reason, But Shimano bearings will run as good as any ABEC5 bearing if they are lubed the same. The carbontex drag is hands down an improvement, on any reel that doesn't use them.