What's the best way to swap em out for longer ones?

 

Hit them on the end with a hammer and they will fall back out through the stud hole. Have the new ones pressed in, or you might be able to draw the new ones in with a couple washers, a nut, and an impact wrench...

 

They aren't like welded in or anything? That doesn't seem very strong/sturdy to me?

 

Nope. They are pressed in.

 

Seems like an easy deal... almost too easy ':\