Will cheaper implant be just as good as more expensive one?

Q. Hello, i have lost my front tooth in accident few years ago. My dentist attached artificial tooth to my healthy tooth; however because of it is front tooth i feel very self conscious. When i smile i feel like everyone can see that the tooth is not real. It does not give me any problems other then way it looks. There are significant tissue loos between gum and artificial tooth, so there is some space in between which i hate. I have been considering for a while now to have tooth implant done. I found dentist in London who will do my implant, considerably cheaper. Because i am student i cannot afford very expensive dentist. What my worries is, i am doing implant because i want it to looks as natural as my other front tooth. Because it is front tooth, if it does not look exactly like my other tooth then it will look artificial. Because i am doing this implant only for cosmetic reasons, i need independent opinion from another dentist, what can happen, in worst case. I do not want to spend such an amount of money and then find out that, it actually looks worst. I have one more question. Because implant tooth is not natural, can i use some tooth whitening stuff from internet to whitener my teeth. Again i don’t want that my teeth will turn white and artificial tooth stays darker. How long actually implants last? One more. I was reading that sometimes patients gum is so thin that the implant is visible. Is this happens because dentist did something not right, for example did not consider before that gum was thin, or drilled in wrong place, or you never know what will happen? For example, if first place my implant looks right then it is possible that new years later my gum tissue will get thin and my implant become visible? Thanks for your help. Your sincerely