The seat belt sometimes does not retract properly. It seems that the guide mechanism may not be wide enough which causes the belt to fold slightly when pulled out (minor hassle).
Also the radio will not come on when the car is started about 70% of the time. After turning it off and on again, it's fine. I have seen many reviews about both of these problems in the Tiburon and am sad to say I have them too.
I love this car! This is the second Hyundai I have owned and I've never had a single problem. Hyundai has done an amazing job in the past 3-4 years re-creating their company. And the warranty is the best. When people stop me to ask about my great looking car, I usually get the astonished "THAT'S a Hyundai??" Keep up the good work. And I'll be back to my dealer when the Tiburon comes in a convertible model!
Your radio problem was a recall, which you should have received a letter on this. My radio did the same thing in my tiburon, but I took it up the the dealership and they replaced it at no cost to me.