interior dash lights create a computer problem??

I went today to this place here in puerto rico called dr led. This guy supposedly can do every type of led and install them on " every type of car"... emphasis on "". So when i went in, he tells me i can't change the lights on the dash not only because it is soddered in, ( sorry for the typos im with a migrane) but it can also burn the cluster and computer out and he supposedly heard or had someone that did the change and ****ed his car up... obviously i asked him what gen aveo and he kept saying hatchback. I ended up leaving, but have the question, has anyone that has changed the colors of the lights had a computer problem? Also, Are the bulbs sold separately?