what happens if i color these?

i bought the glamour hair extensions in curly.(althogh its not that curly)anyways i wanted medium brown and jodi said she didnt have that but she had chocolate brown'and that it wasnt that dark.but when i got them they are dark.i do not want to color my hair that dark.so what will happen if i color the extensions myself?i just want a little bit lighter not much.what should i use?and i am also afraid when i do color them that all the curl will fall out.i dont think its fair that we pay  so much money for these.only to have the extensions go straight. thats not right. thanx girls

No, no, no do not color them lighter. Sometimes it might look okay to color a few shades up or down but you have no idea what's under that chocolate brown color. Firey auburn? Blue Black? Mix all those colors together and you have a disaster, and most likely overprocessing (especially lightening) the hair will damage it, causing it to lose it's curl.