First up is Powerage's Powertown...

http://www.renderosity.com/mod/bcs/powertown/101749/

This set when loaded into Carrara immediately shuts down the software without warning or notice. I have never seen anything quite like it.

Well, I played with it for a little while.

If you want to use Powertown, do the following...

1. You cannot try to open up the complete scene, but you CAN open each item, one by one.

2. DO NOT try to open the street layout, THIS is what seems to crash Carrara.

3. Save each building as a Carrara scene file. Each building will appear in the place they are supposed to be.

4. Open the Street layout in DS or Poser.

5. Export to Collada or as an OBJ.

6. Try to import this file into Carrara.

7. The size will be smaller than it should adjust scale to 100%

8. The streets and props won't have any textures, they will be all grey.

9. You can swap out the props (street signs, traffic lights, etc,) with any of the following...[if you want textured props]

www.renderosity.commodbcsschoolblock-streets97358

www.renderosity.com/mod/bcs/traffic-lights/86035/ 

http://www.renderosity.com/mod/bcs/movie-props-street-lamps/97469/

http://www.renderosity.com/mod/bcs/trafficlight-01/52427/     this one is only $3.50

https://www.daz3d.com/streets

This should get you up and running with Powerage's very cool city!