Angelic Wings?

[2xMachina]

^

And if you don't mind +2 la, go Saint. And that template works better with Lesser Aasimar than Aasimar anyway (redundant abilities, and Outsiders can't be Saints). And you get the outsider native type back.

So, for a total of +1 la, get immunities to 3 energy, more resistance to fire, some Su abilities, more +Cha Wis. (Also needs 3 exalted feats and lvl 6 though)