The ecto 1a is also longer as well, you can see this on side views, the backs segment has another seperator, it's hard to explain but the cars were very differnt cars, it easy to point out, besides you thing Dan would let the studios rip apart his first ecto car?

it might be just your eyes messin with ya. since the 1a has much more ‘stuff’ on it, it could appear taller or something. i think they are the same, but i could be wrong. there are some experts here that could tell ya. i do know they have different rear bumpers. the ecto 1 has, what looks to be, an original bumper, while ecto 1a has a red step up bumper.
derek