i was wandering if anybody could tell me how to do custom body work to plastic models like the doors or trunk. i would really appreciate it.
lowridin por vida.  

You can just use regular body filler...it works like a charm. For extra custom parts you can use styrene articles like forks and knifes or sheets.  

be carfull when you use a large knife for like cutting out doors or a trunk or somthin because it can leave a biger gap between the two peices