Hi I am new to this and I have a question. I have a Harbor freight bunker hill security system. I have always used it just to look at whats going on out side. There was a incident in my neighborhood and this system does not help. I was wondering if I can upgrade the cameras in this system and it will record good quality night vision. I am looking to add 2 high quality cameras that will give me at least 100ms of quality night vision. Is that possible or would I also need to upgrade my dvr? If so does any one recommend any cameras that are in the 100-150 dollar range that would give me good quality night vision at 100m.