Originally Posted by The Boy Scout
Exactly. And since the logic of Superman's costume is to protect itself (instead of protecting him or aiding him in his crusade), the changes that are made to it are going to be scrutinized much more heavily in comparison to characters like Batman or Daredevil. You could keep the suit as is and simply say that it's made out of a very durable alien material.
It's the only thing he has available that's able to withstand a lot of damage.
He wants to stand out as a dramatic example.
He purposely wants to present himself as the antithesis of Zod and prove that not all aliens are bad. That, even though he is dressed as "one of them," he is still "one of us."
I think this element would have to be played up to explain the cape. Which unlike the costume which can be argued is needed due to it's "invulnerability" perhaps?
The cape is clearly just a fashion statement.