I am new to CAD software and am looking to learn how to layout and design fire alarms as well as security systems with AutoCad. I have already decided to purchase one of the Autodesk products since they are obviously the standard, but am not sure which product would be appropriate for my needs. I would of course like to purchase the least costly version necessary for my needs, but to not want to sacrifice any tools/features that I might need. My main tasks would be to take already designed DWG files provided by architects/engineers and to add a layer(s) showing symbols representing fire/burglar alarm devices as well as their associated wires. I assume it would be very similar to a version that an electrical designer/contractor would use to design the building's electrical and lighting systems.

I was originally leaning towards AutoCad LT, but after doing more and more digging, now it seems like MEP might be more suited to what I would be doing. As I mentioned, I am not experienced with CAD software and whichever program I decide on, I am sure that there will be a heavy learning curve; I just want to make sure that I start off on the right foot with the correct software.

I would appreciate any input as to which product would most appropriately complete this task; as well as any recommended books/tutorials to get me started.

Thanks for the help!
John