2002 MGM - Install automatic car starter?

Hi all,

We are planning to get my mother an automatic car starter for her 2002 Mercury Grand Marquis. Her car has a keyfob that unlocks front and rear doors, panic button, and has a button to unlock the trunk. Would a basic automatic car starter still allow her to use the existing keyfob, or do we need to get a "deluxe" car starter to allow her to control the trunk, etc. I know that she won't be able to pop her trunk until the the key is in the ignition, but are there any other issues/problems with an automatic car starter for that make and model. She has an automatic transmission so that won't be an issue. It sounds like from what I've read on different forums before asking this question that buying a basic automatic car starter will disable her keyfob, unless we buy a bypass system for it, which runs almost as much as a deluxe system. Am I interpreting that correctly, or will her keyfob work just fine without a bypass? Thanks in advance