Hi, I have some questions regarding Keyless Entry system for my '97 Maxima SE.

My SE did not come with Remote Entry system, and I was wondering if it's possible to add Remote Entry system to my car.
I have seen some remotes for sale on ebay, and also direction to make them work. My question is... are those remotes and installation direction only for Maxima which originally come with the system? or will it work for my Maxima, also?
Another question is, do I need to have my car ID # to install remote entry system? If I do, how can I obtain it? Since I bought this vehicle as used, I do not have original car ID plate which supposed to come with keys.

If anyone can answer these questions, I would appreciate it.

Thank you in advance.