I want to put an automatic remote car starter?

I have installed many remote start kits on many different vehicles. I highly recommend you get a professional to install it. Your 99 grand am likely has an antitheft ignition on it that will need to be wired properly to avoid activation. It will not affect or disable the anti theft if wired right. Proper wiring diagrams will be needed as well. To do the job properly it takes time to do it neatly and safe(no shorts to cause fires). Essentially a remote takes the place of you starting the car through the circuits in the remote and will not harm your computer.Properly done a good quality remote starter will work without issues the life of the vehicle. I personally prefer the Autostart brand (In Canada)