How can I create a downtown with a downtown terrian? It isnt avalible in the creation of a custom downtown. Will I have to take the base downtown and bulldoze everything in it to make it completely custom?

I have no idea--I wanted to add roads in SC4 to Downtown last night and couldn't see a file for it. I know Mootilda was trying to find a way to pull the file from an existing neighborhood for HoodReplace from reading that thread but it doesn't look like that's possible yet (if ever).

SonicBoom12: You can always use HoodReplace to copy the terrain from the Downtown template to your custom Downtown.

Sunbee: Adding roads is much harder if you don't have the original SC4. Unfortunately, I don't know of anyone who has re-created the Downtown SC4.

I can't find down town on the program. Do I make my custom down town with any terrian and then replace it wwith down town's one? I also kind find down town on hood replacer.

Yeah, make your custom downtown with any terrain (probably be better to use an undecorated terrain) and then, from a neighborhood with the EA downtown you should be able to copy from the EA downtown across. The tutorial for HoodReplace is in the first page of comments on the HoodReplace thread, and it's pretty straightforward--I can follow it! (You would think that with how often I use this program, I'd have given you a more correct answer at first, but no, that's beyond my abilities. I can give Pleasantview beaches, though.)