A pair snap ring pliers is about the only special tool you need. What do you call "worn" on 1st and rev. If you are talking about the corners of the gears looking kind of chewed up, almost all of them look like that and it doesn't hurt anything. The first sign of trouble usually appears with the transmission jumping out of 3rd gear. This is usually caused by a worn synchronizer and shift fork. If its not jumping out of gear, I would leave it alone.
