We called 1-866-781-1333 and asked for the mousesavers discount. They gave us $8 off each person. They give you a confirmation number - that is all you need. (To find this discount we went to Mousesavers dining page, got the link to Orlando Coupons, then went to thier dining page and clicked on Makahiki Luau.)
Park admisiion is not required. Just drive up to the gate and give the confirmation number. They let us through w no parking fee. The eariest we could enter the park was 5:00 for a 6 o'clock luau. Since we got to the parking lot at 5 - we found a space close to the entrance.
Then we gave the confirmation number again at the park entrance. Once we were in we toured around a bit. We checked in at the Luau podium about 5:45 and we were seated prompty at 6.
The luau lasted 2 hours. At 8 we went on some rides and saw some exhibits. Then we went to the Shamu show. Afterwards we did some shopping and watched the fireworks show. The park closed at 10 that night.
It is a great deal. Let me know if you have any questions.