So, potential only has to do with how long a horse will stay at or near his peak, or does it have anything to do with how good a horse might become?

I raced my first 4 star potential last night from Tender Glow and Personal Plane and while it was easier than normal to win on both dirt and grass, the horses stats weren't that impressive.I've had much better 3 star potential horses statswise but I was able to win well into the horses eighth year.