voice box sucks it was so 90's. and also it causes more problems. think about it, it draws attetion. people will f#c* with your car just to hear it talk.
it all depends on how confident and comfortable you are with putting it in yourself. just make sure you read the install manual thougroughly and double check all wires before making connections and you should be ok. the 550 can take a little while to install for a beginner, so free up a day, start early, and don't rush and you'll be done in no time.