Zathraas said:
Is there a trade off, ie, lose Summon Familiar?
Of course there's a trade off!

I don't have the specific rules in front of me, so I can't be exact, but you can no longer specialize in a school of magic normally, instead you specialize in illusion and transmutation and must choose 3 barred school out of abjuration/conjuration/enchantment/evocation/necromancy. This specialization in Illusion/Transmutation gives you +2 to spellcraft & 1 extra spell per day from
either of those two schools.
At 5th level instead of a bonus wizard feat, you get limited spell knowledge, which means instead of 2 new spells a level, you get 3 illusion/transmutation spells. Your familiar can also shapeshift now into another type of familiar available to 1st level wizards (you lose previous familiar benefit and gain new type benefit).
At 10th level you lose the bonus wizard feat and get "override transmutation" - if you fail a saving throw on a transmutation spell or spell-like ability that has a duration longer than instantaneous, you get a second saving throw one round later.
Roughly, I think that's it, but don't quote me on it. Obviously you also have to be a Changeling to do this, so that carries some pros/cons.