It highly depends on which doors you are talking about. If you have doors that have huge holes all over them then without filling the holes and deadening you are going to get massive amounts of backwave cancellation.
If you have relatively sealed doors to begin with of course some midbass is possible.
And you say the pg's are average at best but i got rid of my ads 346cs comps that you currently have a set of and the pg's have them beat hands down. Maybe the ones you heard weren't installed properly, especially if you dont beleive in deadening.