Super Saiya-jin-
This is when a Saiya-jin exceeds his maximum power level. This can only be achieved by a person with pure heart, (This counts pure Evil to) and can only happen when you become super pissed. This level is shown when your hair turns Golden, and your eyes turn greenish. This level has been achieved by all Saiya-jins which only excludes Pan and Bra who never reach the pl needed (Note:Saiya-jins who have a mother or father who is Saiya-jin, or a mother of father that his human tend to go Super Saiya-jin at an earlier age)

Ultimate Super Saiya-jin-
This level is contained when you exceed your maximum power level as a Super Saiya-jin. This tends to have a harsh effect on your muscles as they tend to bulge emensely. This level is only really used in the cell saga , and you eyes are White. This stage has only been reached by Trunks Goku (never uses it) Vegita and Brolly.

Super Saiya-jin 2-
This stage is more powerful than Super Saiya-jin or USSJ. This is probably the best stage in dbz (ssj3 uses lots of life energy and ssj4 is not in dbz) This stage is shown when your Goldish Hair gets bushier, and bolts of electricity run through your body. This stage has only been achieved by Gohan, Vegeta, and Goku.

Super Saiya-jin 3-
This is the most powerful Super Saiya-jin level in dbz. At this stage you become EXTREMELY powerful, and you lose your eyebrows. This stage is shown when your hair becomes VERY long. This is the easiest Super Saiya-jin level to reach (all ya gotta do is be able to go ssj2 and then train hard). This stage has been achieved by Goku and Gotenks.

Super Saiya-jin 4-
This is the most powerful Saiya-jin form. Instead of your hair being Gold in this stage, it becomes the color of your normal hair color, but more of it like a Super Saiya-jin. Instead of a shirt, red fur covers the chest area (unless your gogita whos special so he gets brown fer), and they where extremely off looking paints. And they're tails also grow back turning a purplish red color. The only people who have reached this stage are Goku, Vegeta, and Gogeta.

OOZARU-
This is when a Saiya-jin looks at a full moon, and he will then turn into a Giant Ape. This makes the Saiya-jin Power level 10 times stronger than it's normal self, but it still isn't as strong as a Super Saiya-jin. All Saiya-jins who have tails can reach this level. All tails grow back after being chopped off, except for Goku, who found a way to cut it off with our it growing back (later on this seems to be a new trend as after the saiya-jin saga tails are not seen again till dbgt). The only problem is that this stage is totally uncontrallable, unless you're had special training.

GOLDEN OOZARU-
This level of OOZARU is only achieved when you are a Super Saiya-jin and look at a full moon (or earth). Here you turn into a Giant Monkey, but your hair is Golden, and you're a little more powerful than a Super Saiya-jin 3. The only bad part is that this stage is nearly uncontrolable (bebi vegita can)