M20's How Do You DO That? suggests that they'd need Life 3 to affect their body-based Attributes in such a manner (Life 4 to affect others). This includes Physical, Social, and Mental Attributes, although Mental changes might not be physically obvious.
So long as the changes remain within the normal human range – between one and five dots – and do not radically and abruptly alter the subject’s normal appearance (as it would if you suddenly turned a skinny dude into an underwear model), the alterations remain coincidental; if the changes go beyond the normal human maximum, however, or make other radical changes to a person’s appearance (huge eyes, antlers, etc.), then the alterations become vulgar. Radical and permanent changes may also (Storyteller’s call) inspire Genetic Flaws, as detailed in Appendix II of Mage 20, (pp. 648-651).
Typically, a mage needs four to six successes to change her shape permanently, or eight to 10 successes in order to transform someone else the same way.
In the case of [making] increased Attributes [permanent], they cost one-half of the normal experience-point expense if they’ve been raised by
permanent Life-Sphere Effects. If the player does not pay the points to retain those Attributes, then the character suffers a Paradox-inflicted rotting disease, organ-rejection, nasty steroids-style side-effects, or other symptoms of bodily rejection. That rejection process inflicts one lethal health level in damage per day (no soak possible) until the player pays the necessary experience points in order to “stabilize” the character’s transformation. (Again, see the Genetic Flaws section of Mage 20’s Appendix II.)