I know who you are talking about regarding the tutorials. Their name escapes me but I know that group is no longer in business; they had actually referred some business to me a couple of years ago as they were winding things up. 

The .ai city tutorial you are thinking of (at least the one I'm thinking of) was done just before the replicator was integrated with Carrara. While it's anothor way to do things, the replicator is is the fastest. Is that something that you want to figure out or would you like me to show a method?