“Here's something that will really bake your noodle later on.” -The oracle form The Matrix.
Ecto-1 and Ecto-1A are VASTLY different. But in EGB, the name is still Ecto-1 but is so different it's not even funny. It's got rollcages, really weird lookin' steel bumpers, and new high-tech stuff.
A side-note, Ecto-2 is the copter, and Ecto-3 is a really weird motocycle that the GBs can make by taking various parts off the Ecto and putting 'em together. Only seen in one episode (i think.) The only one I can rememeber they used it in was the one when the cartoon character comes to life and terrorizes New York. (Name of episode anyone?…)