Hi, I have one of these now, and i know they are mean little buggers but are they gonna be a threat to anything in my 90gal signature tank do u think? If so I may just take him back, which i dont really want to do. He was pretty beaten around the mouth as he was in a tank with a breeding pair of Flowerhorns (the guy didnt know they had laid eggs) and a Jewell, so i felt sorry for it and really liked the look. Any thoughts welcome!!!

Not a chance.
Exodon are like small pirhana, so treat them roughly as such. They need a shoal or else they are not going to do well, plus your cichlids are likely to cause a fair few problems with regards to teratories. There is a species profile on Exodons wich I suggest you read.
I suggest you put the Exodon in a seperate tank with the view to getting more, or give it back to the shop.

Thanks, I was plannin on takin it back tomorrow, looks a done deal now.