TI provides the rom for the TI-83+SE for free as part of their developer's kit, so you can just download it. All you have to do is rename the extension to .rom No need to romdump or get one "illegally".
Shhh don't tell them, though :O if they read this post they will make the SDK require your calc ID
j/k I bet they would have figured by now but again this is TI we are talking about. I hope they won't ever do anything to prevent this
*cough* not that I offered anything *cough*