That is quite a bit of light for the size. I've only got 370watts over my 55g and i keep much and safely. You would be able to keep all high light required corals. You will need to watch out for low light corals. How high up are you going to keep these lights from the surface of the tank.
Yes there is a such thing as too much light. You're getting close, but not quite there. There is a set back to so much light. Yes corals will grow well, you will find that if you buy a coral from a tank that has less light then you (which will be almost all other tanks), then you'll need to either decrease your photoperiod to 3-4hrs a day and then in 3days increase to 5hrs and in the 3days 6 and so forth until you get the photoperiod you want. Another thing you can do is put 3 screens in front of your lights and do the same. If you don't do this... you will bleach all your corals and have nothing.