What do you do on saints row 2 after you beat every single mission?

You can replay your favorite missions again,you could go beat the side missions to get achievements and get bonuses also 100%,you can go buy the rest of cribs and cars that you have yet to get.Or you can go on a rampage if your bored.There are those hidden item things you can get for 100%.Honestly there's alot of stuff to do after you finish the main story.