Adding to the others- All Spartan IIs had special genetic characteristics (I don't know what they are) that made the augmentations far more effective than they were on a regular human (I think 5x as effective or something). These genetics are extremely valuable, and were essential to the ability of a Spartan II over the later generations. However, a few of the Spartan IIIs had these genetic characteristics, and were considered nearly as good as Spartan IIs. These Spartans, including Noble Team, were given access to many Spartan II technologies, including the MJOLNIR armor. Long story short: Noble Team (Excluding Jorge who was a II) were all Spartan IIIs who had the same, unusually potent, response to augmentations as the IIs.